Question: I have been getting bad migraines for two years every two to four weeks, with severe pain in the right side of my head. A CT scan was normal and Inderal did not help.
A CT scan will always be normal in a migraine patient, but may be used to exclude other causes of a headache. If all other causes have been excluded, and your symptoms fit the criteria for a migraine, then further treatment can be tried.
Inderal is a very effective medication in preventing migraines in many patients, but there are always those in which it does not work. There are several other medications which can be used to prevent migraines if Inderal does not work, and here are preparations that can be used to treat any migraines that may occur. All the preventative medications require a prescription, and you will need to discuss with your general practitioner which ones you should try. It is a matter of trial and error to see which ones work. Medications that may be used include methysergide, cyproheptadine, clonidine, pizotifen, verapamil and naproxen.
Treatment regimes vary from simple over-the-counter regimes to prescription medications. A simple regime that does not require a prescription is to take three aspirin and two Mersyndol every four hours, starting as soon as the migraine starts, but this will cause some drowsiness. The best treatment is often an Imigran tablet, inhaler or injection. Other injections and tablets are available from your doctor.

Question: How many different causes are there for headaches?
This is going to be a long answer, because a headache is probably the most common symptom to be experienced by the human race, and may be associated with problems of any of the multiple complex structures in the head, or disorders of many of the body’s other organs. Fatigue, stress and anxiety may in themselves cause a headache, or may trigger muscle spasms in the temples and scalp that are responsible for the pain. Any infection, by a bacteria (eg. tonsillitis, sinusitis, ear infection, bronchitis, urinary infection), virus (eg. influenza, common cold, glandular fever, hepatitis), fungus or parasite (eg. malaria), may cause a headache, as may a fever (see separate entry) of any cause.
Injury to any part of the head may cause a headache, but sometimes, and very seriously, the headache may occur some days after the injury due to slow bleeding from a leaking vein within the skull. A headache is more significant when not associated with any other symptoms elsewhere in the body. The most common headaches to fit into this category are tension headaches, migraine and cluster headache.
A tension headache causes a dull, persistent pain with varying intensity that is often described as a pressure or tightening around the scalp. It occurs as a localized band around and across head, and is not aggravated by exercise or alcohol. Tension headaches are episodic, often in association with stress. Depression and anxiety are common accompanying symptoms. The pain may last for 30 minutes or a week. Muscle spasm headaches usually have a cause (eg. stress, infection, psychiatric disturbance, eye strain), and if possible this should be rectified. Simple medications are readily available to ease both the muscle spasm and pain.
Migraines are often associated with visual symptoms including flashing lights, shimmering, seeing zigzag lines and loss of part of the area of vision. They usually occur on only one side of the head, are described as throbbing, and cause intolerance of exercise, light and noise. Nausea and vomiting are common. Migraines occur periodically, and may last for a few hours to several days. The patient often looks pale and drawn. There are now effective medications available to both prevent and treat migraine.
Cluster headaches are not common, but cause a very characteristic pattern of headache, usually associated with excess sweating of one or both sides of head. They occur in episodes once or twice a year to cause severe pain around or behind one eye which spreads to a temple, the jaw, teeth or chin. They often begin during sleep, and other effects may include a red, watery eye, drooping eyelid, altered pupil in the eye, stuffy nose and flushed face. Cluster headaches may be triggered by alcohol, temperature changes, and wind blowing on the face or excitement. They usually last for 15 minutes to three hours, and are named because of their tendency to occur in clusters for several weeks. An unusual but effective cure is to breathe pure oxygen for 15 minutes.
Many people fear that their headache may be due to a brain tumor, but this is actually very rare, most brain tumors causing other symptoms that lead to their diagnosis well before a headache develops. Cancerous and benign tumors may develop not only in the brain tissue itself, but in the other structures within the skull such as the pituitary gland, membranes around the brain (meninges), sinuses and eyes. Most brain tumors are benign and can be cured by surgery.