The treatment of chronic headache disorders can include medications which are typically used for depression, epilepsy, and high blood pressure. Even though these medications were initially designed for one purpose we utilize them to try and prevent headaches form occuring. Therefore, if your doctor is prescribing an "anti-depressant" that does automatically mean he/she thinks you are depressed. You should ask the doctor why he/she is using that particular medication.
Second if you are having daily headaches this could be do to analgesic overuse. Meaning if you use to much pain medication it can actually induce headaches. The fact that they have found no structural lesion is good, however it does not explain the recurrent headaches and back pain. Have you been screened for connective tissue or inflammatory disorders such as lupus?
What I would recommend is a second opinion with a neurologist who specializes in headache. If you are in the area we have an excellent headache center. They can review your case and recommend a treatment strategy to try and reverse this negative cycle. Good luck.
may take a couple of weeks to start working, too.
and also it would be useful to know which one you were prescribed. Depression of a clinical nature can be diagnosed by asking certain questions of yourself do you wake in the night for no reason or early in the morning do you get tired alot more than is normal do you get angry or fly off the handle easily? there are many depression rating scales on the net go find one and see how you do. Christie is right it may be treatment for pain often we can get into a cycle of pain and your body responds or learns to keep tense all the time waiting for the pain to arrive you breath differently this causes hyper oxegenation so you bathe your nervous system in alkaline affecting how your muscles respond and your nerve endings get irritated. Im in england so we have different names for drugs here but I'd be interested to know which one you were given I work in primary care and devise guidelines for the treatment of depression and the de-stigmatisation of the disease. If you are treated successfully and you take the meds religiously the headahes are unlikely to return once you've completed your treatment as you will have conquered your cycle of pain make sure you look at your breathing though do some relaxed breathing excercises in the morning before you start your routine . good luck