Imitrex and medicines

I have had migraines since I was in my early 20's, I am now 56; however, I was never diagnosed and just endured them. About 6 years ago a neighbor gave me an Imitrex when I complained of a headache that would not go away. In 20 minutes it was gone! Got my doctor to give me a prescription. Originally, after taking Imitrex I would get a bit sleepy, but I don't get that side effect anymore. What I do experience about 90% of the time is joint pain when I move. It does not last but a day or less and is a side effect I can live with since it gets rid of the migraines. Like a lot of medicines, Imitrex is not for everyone and side effects vary.