Shingles typically appears as a rash or crop of blisters on one side of your body, often around the waistline.
The pain of shingles tends to be burning or tingling, and often affects only one side of your body. You may feel stabs of pain when someone simply brushes lightly against the affected skin or a breeze wafts over it.
Some people who have had shingles can develop a persistent pain called post-herpetic neuralgia.
Read more about shingles and the shingles vaccine.
2. Cluster headaches
Cluster headaches are excruciating attacks of pain on one side of the head, often felt around the eye.
They begin quickly and without warning. The pain is very severe, and is often described as a sharp, burning or piercing sensation.
People often feel restless and agitated during an attack because the pain is so intense, and they may react by rocking, pacing, or banging their head against the wall.
Read more about cluster headaches.
Find your local headache clinic.
3. Frozen shoulder
This condition not only is extremely painful but also can last for several years if not properly treated.
In frozen shoulder, the joint becomes so tight and stiff that it's virtually impossible to carry out simple movements, such as raising your arm. Daily activities like taking off a T-shirt, lifting a kettle, putting on a coat or even combing your hair become an ordeal.
It's not clear what causes frozen shoulder, but it can happen after a shoulder or arm injury, and is more common in people with diabetes.
Read more about frozen shoulder.
4. Broken bones
A broken or cracked bone is known as a fracture. Common examples are a broken ankle, broken hip, broken arm or broken nose.
If the break is small, it's possible you might not feel any pain at all but, usually, a broken bone really hurts, especially when you try to move it. The pain is often described as feeling like a deep ache.
Broken bones can heal by themselves, but they may need to be lined up and fixed in position so they set properly. As a general rule, the older you are and the bigger the bone that's broken, the longer it will take to heal.
5. Complex regional pain syndrome (CRPS)
CRPS is a severe, long-lasting pain that can appear shortly after an injury, such as a fracture, burn or cut.
The burning pain of CRPS is continuous and intense, and often completely disproportionate to the severity of the original injury.
The pain is usually confined to the previously injured limb but can sometimes spread to other parts of the body.
The skin of the affected body part can become so sensitive that just a slight touch, bump or even a change in temperature can provoke intense pain.
Read more about CRPS.
6. Heart attack
If you have a heart attack, you usually get a pain in the centre of your chest – often described as a sensation of heaviness, tightness or squeezing – that can be so bad it causes you to collapse.
The pain can feel like really bad indigestion, and sometimes spreads to your jaw, neck, back, arms or stomach.
If you suspect that you or someone else is having a heart attack, call for emergency help immediately.
Find out more about heart attack and read 64-year-old Derek's real-life description of what it feels like to have a heart attack.
7. Slipped disc
One of the most common causes of back pain is a slipped disc. It's often the result of a twisting or lifting injury. One of the discs in the spine ruptures, and the gel inside leaks out.
Most people with a slipped disc experience sudden and severe lower back pain. It's usually eased by lying down, and often made worse by moving your back, coughing or sneezing. A slipped disc can also cause leg pain.
Read more about slipped disc.
8. Sickle cell disease
A sudden episode of pain, known as a pain crisis, is one of the most common and distressing symptoms of sickle cell disease.
The pain, which usually occurs in the bones and joints, can vary from mild to severe and last for up to seven days.
Some people may have an episode every few weeks, while others may have fewer than one a year.
Read more about sickle cell disease.
People with arthritis endure constant and often disabling joint pain, usually in the hips, knees, wrists or fingers. The pain can come on suddenly or over time, and is often linked with muscle aches and stiffness in the joints.
Various different types of arthritis – including rheumatoid arthritis, osteoarthritis and lupus – can cause joint damage.
Read more about arthritis.
Find your local arthritis support services.
A migraine typically feels like an intense headache on one side of the head. The pain is usually a moderate or severe throbbing sensation that gets worse when you move and prevents you from carrying out normal activities.
In some cases, the pain can occur on both sides of your head, and may affect your face or neck.
Migraines can cause vomiting and extreme sensitivity to light and sound. Sometimes, in cases of severe migraines, the best thing to do is find a dark, quiet place to lie down until the pain passes.
Find out more about migraine and read a true-life account of what it's like to have migraine.
Find your local migraine clinic.
Sciatica is the name given to an aching pain running down the leg. It's caused when the sciatic nerve – the longest nerve in the body, which stretches from your back to your feet – has been pinched or irritated by damage to the back.
Sciatica is different to general back pain. The pain of sciatica hardly affects your back at all – instead, it radiates out from your lower back, down the buttocks and into one or both of the legs, right down to the calf.
Read more about sciatica.
12. Kidney stones
Passing a kidney stone can produce a sudden, sharp, cramping pain in your lower back or the side of your abdomen, or occasionally in your groin. The pain may last for minutes or hours, with pain-free intervals in between.
The pain often begins in the middle of the night and can be so severe that those who experience it may feel the need to go to A&E.
Most kidney stones are small enough to pass out in your urine, and the pain disappears once the stone has been passed.
Read more about kidney stones.
Appendicitis is a painful swelling of the appendix, a finger-like pouch attached to the gut wall. It's most common in children, who typically complain of pain in the middle of their tummy that comes and goes. The pain then shifts to the lower-right side of the tummy and gets worse.
Appendicitis is a medical emergency that usually needs an urgent operation to remove the appendix before it bursts.
Read more about appendicitis.
Watch this animation to learn about the causes and treatment of appendicitis.
14. Trigeminal neuralgia
Trigeminal neuralgia, also known as Fothergill's disease, involves bouts of severe pain on one side of the face that comes and goes unpredictably in sudden attacks.
Some people say the pain feels like an electric shock shooting through the face, while others describe intense sensations of burning or stabbing.
Read more about trigeminal neuralgia.
15. Acute pancreatitis
Acute pancreatitis is the swelling of the pancreas, a banana-sized organ that's part of the digestive system. The most common symptom is severe abdominal pain that appears suddenly.
This dull aching pain often gets steadily worse and can travel along your back or below your left shoulder blade.
Eating or drinking, especially fatty foods, may also make you feel worse very quickly. Leaning forward or curling into a ball may help to relieve the pain, but lying flat on your back often increases it.
Read more about pancreatitis.
Gout is where swelling and severe pain develops in a joint, often the base of the big toe, to the point where moving or even touching the toe can be agony. It's one of the most painful forms of arthritis.
During an attack of gout, the joint starts to ache, before swelling up and becoming red, hot and extremely painful. Attacks can last between 1 and 10 days.
Read more about gout.
Endometriosis is the spread of womb cells outside the womb, mainly around the lower abdomen.
While some women with endometriosis have no symptoms at all, others have lots of pain, including pelvic pain, period pain, and pain during and after sex.
Michelle, a mum of two, describes life with endometriosis.
Read more about endometriosis.
18. Stomach ulcer
An ulcer is a sore or hole that forms in the lining of the stomach. A stomach ulcer can cause a burning pain in the abdomen, often between meals.
An untreated ulcer can burn through the stomach wall, letting digestive juices and food leak into the abdominal cavity, causing disabling pain.
This is called a perforated ulcer and is a medical emergency that usually needs to be operated on immediately.
Read more about stomach ulcer.
Fibromyalgia can cause aches and pains all over the body, typically in the back of the neck, shoulders, lower back, hips, shins, elbows and knees. People with fibromyalgia often say they ache all over.
Quite often, the pain and stiffness is worse in the morning, and you may have more pain in muscle groups that you use repetitively.
Read more about fibromyalgia.
20. Pain after surgery
It's common to have some pain after surgery, though the intensity of the pain will vary according to the type of operation.
But too much pain after surgery is not a good thing, and you should never feel you have to "tough it out".
There are lots of effective painkillers on offer to keep your pain after surgery under control. In addition to making you more comfortable, well-controlled pain will help you get better faster and prevent long-term problems.
Read more about what happens after having an operation.