I'm having a problem opening my left eye when I wake up in the morning. This has been going on for about 3 months. I don't know what the problem is. Should I see my regular doctor or should I see an eye specialist?

Eye doctor. Go see an eye doctor. It is an eye problem, so see an eye doctor.
Eye specialist. You should see an ophthalmologist to evaluate your eyelid function. There are several possible reasons for inability to open an eye.
It . It is possibly you might have inflammation of the lids, known as blepharitis. It's a non-infectious, inflammatory type of condition. You need to see your eyecare professional for proper diagnosis and treatment.