Short-term pain (acute pain) can be caused by a number of things, such as a burn, a sprained ankle or toothache, and tells the body that something is wrong.
It can be severe but it doesn't last very long.
Words used to describe short-term pain include 'sharp', 'stabbing', 'burning' and 'sore'.
If this pain persists you should consult your doctor.

Long-term pain (chronic pain) happens every day or comes and goes. It can be caused by many conditions including arthritis, pain in the lower back, angina, leg ulcers or stomach ulcers.
Chronic pain can often affect your quality of life. Words associated with long-term pain include 'dull', 'throbbing', and 'deep'. Pain is classified as being mild, moderate or severe.
Most common aches and pains, such as headaches, migraine, period pains, toothache, sore throat, muscle spasms, some nerve pain (neuralgia) and fever are in the short-term mild to moderate category. You can buy pain relievers (analgesics) that will help to reduce short-term or acute pain 'over the counter' (sometimes shortened to OTC) from your pharmacy.
This means you don't need a doctor's prescription to get them. However you should only use them for a few days at a time. If the pain continues for more than that, you should go back to the pharmacist or see your doctor.

Analgesics form the largest category of medicines sold over the counter in pharmacies. Most products contain aspirin, paracetamol or ibuprofen, alone or in combination with codeine or dihydrocodeine. Most could be used to treat a wide variety of aches and pains, but some are aimed at a narrower range of specific indications.
They are suitable for headaches, cold and flu pains, toothache, fever, period pain and for the relief of muscular or rheumatic pain. Only where indications differ, particularly from the general list, are they quoted.
Aspirin has antipyretic, analgesic and anti-inflammatory properties. It acts by inhibiling prostaglandin production. However, it causes gastric irritation and can damage the gastric mucosa. Therefore it should not be taken on an empty stomach and is contra-indicated in patients with gastric ulcers. Since an association was confirmed between aspirin dosage in childhood and Reye's syndrome, the rare brain and liver disease, aspirin has not been recommended for children under 12 years of age.
Paracetamol{UK}(Acetaminophen {USA}) has analgesic and antipyretic properties, but little anti-inflammatory action, so is less useful for muscular problems. Overdosage with paracetamol{UK}(Acetaminophen {USA}) causes hepatic damage which may not become apparent for four to six days. Patients should be advised not to exceed the stated dose.
Ibuprofen, like aspirin, has analgesic, anti-inflammatory and antipyretic activity. Ibuprofen can also damage the gastric mucosa and must always be taken with or after food or with milk. Asthmatics are advised to consult their doctor before taking ibuprofen. Certain brands of ibuprofen are available as GSL in 12 tablet packs.
Codeine and dihydrocodeine, both morphine derivatives, are the strongest analgesics available for OTC sale. They are only available for OTC sale in combination products at relatively low doses.
Packs of paracetamol{UK}(Acetaminophen {USA}) need to carry the warnings: "Immediate medical advice should be sought in the event of an overdose, even if you feel well," and "Do not take any other products containing paracetamol{UK}(Acetaminophen {USA})".

Topical analgesics, applied externally to relieve pain, can be divided into two classes: the non-steroidal anti-inflammatory agents, and the rubefacients or counter-irritants. Topical analgesics are indicated for muscular and rheumatic pain, fibrositis, sciatica, lumbago, sprains, strains, bruises and stiffness, and unbroken chilblains.
Topical NSAIDs such as piroxicam, felbinac, diclofenac, ibuprofen, ketoprofen and benzydamine probably act systemicallyand locally, and are now widely used for sports injuries, sprains and strains.
Some topical NSAIDs are formulated in alcohol gels which provide a cooling effect as they dry. See analgesics-oral section, for warnings about ibuprofen, which apply to all NSAIDS.
Rubefacients or counter-irritants contain methyl, ethyl or other esters of salicylic acid, a mild topical irritant, and volatile oils such as camphor and menthol which cause local vasodilatation and mild analgesia. Other ingredients include capsicum, a potent irritant. These agents should not be applied to broken skin.
Local anaesthetics such as benzocaine and lignocaine are included in some topical preparations where they relieve pain by numbing the area.
Local pain is produced as a reaction to an adverse condition and patients with persistent pain are advised to consult their doctor.