What Causes Left Sided Headaches Above Ear?

I ve been having daily headaches the past few months, mainly on the left side above my ear. They ve become more intense and I ve noticed it s worse when I cough, or bend over, whenever pressure is great. They ve gotten worse and extremely painful at times. I wear glasses with bifocals and the prescription is old. I can t wear them to see up close, only far away. But it doesn t seem like the glasses are causing the headaches. They are very spuratic at times, but almost constantly now. I m starting to get worried.