Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with your doctor.
Without the ability to examine you and obtain a history, I can not tell you what the exact cause of your symptoms is. However I will try to provide you with some useful information.
It sounds like you have what is called chronic daily headache, it sounds like it is almost a daily headache that is always there but gets worse at times. There are several causes of headaches. Headaches can be divided into primary and secondary. Primary headache disorders are headaches without a direct cause. These are diagnosed after secondary causes have been excluded. In the setting of a normal MRI, a secondary cause of the headache, such as a tumor or vascular malformation, becomes less likely, but there are still some secondary causes that would need to be excluded.
One cause of chronic daily headache is benign intracranial hypertension, also called pseudotumor cerebral, or idiopathic intracranial hypertension. It is a disorder characterized clinically by headaches and vision loss, and sometimes tinnitus (ringing in the ear). Dizziness may also be a symptom. The headache is usually global (all over the head) and pressure-like; the headache presentation can be variable. BIH predominantly occurs in people who are overweight, women, and those taken specific medications such as retin-A (the acne medication), vitamin A, and tetracycline antibiotics. The finding of papilledema implies increased pressure of the fluid around the brain (called cerebrospinal fluid), causing the optic nerve (the nerve to the eye) to be swollen. Prolonged pressure on the nerve can lead to vision loss, so if papilledema is present for prolonged periods (days to weeks), vision and visual fields should be closely monitored. It is diagnosed based on clinical findings and the finding of a high cerebrospinal fluid pressure on lumbar puncture. Other tests may include specific types of brain MRIs and an MRV.
In treating chronic headaches such as in yourself, the treatment should include two types of medications: preventative therapy and abortive therapy. Preventative therapy is a medication that would be taken every day regardless of whether or not a headache is prevent. This type of medication is used to prevent headaches from occurring, and there are several types including but not limited to beta blockers such as propranolol, calcium channel blockers such as verapamil, and others including topamax, depakote, elavil, etc. A lot of these medications were invented for other uses and are used not only for headache but also epilepsy and depression. They have proven very effective in preventing headaches. If one does not try, other trials of different ones should be attempted, or combinations of them; if elavil didn't work with you, another one or combinations of more than one may. The second medication is abortive, meaning it is used when a headache is coming on. The medication used depends on the nature of a headache. If it is a migraine type headache, a group of medications called triptans can be used. And so on. However, with frequent use of abortive medications including triptans, tylenol, advil, and others, medication overuse headache occurs. This requires a specific treatment in which the over-used medications are slowly stopped and replaced with more long-acting medications. Tylenol with caffiene, and similar medications, can cause medication overuse headache if used too frequently. Lyrica, which is used for fibromyalgia, can be used for chronic headaches too.
One of the most common causes of headaches in people with chronic headaches is called medication rebound or medication overuse headache: medications as simple as tylenol or advil if used too much can cause rebound headaches that are even worse then the headaches for which the medications were started for. This is very common and is most likely to occur with use of any medication for your headache more than a few times a week. It can occur with all the commonly used headache medications such as ibuprofen, triptans (such as imitrex), fioricet, and commonly with any type of narcotic such as tylenol #3, dilaudid, percocet, etc. The treatment is difficult, but basically involves weaning off the offending agent and replacing it with another that is later weaned off, combined with a more long-term solution. This should be done under strict guidance by a specialist, preferably a headache specialist, or else the headache will not improve and withdrawal side effects can occur.
You may benefit from evaluation by a headache specialist: a neurologist specialized in headache medicine.
Thank you for this opportunity to answer your questions, I hope you find the information I have provided useful, good luck.