What Causes Sharp Pain On The Left Side Of The Head?

I am a 43 yr old female. I am not 5’6” and 132lb. I do not smoke or drink. For the past month, I have experienced occasional sharp, localized pain on the left side of my head. The pain is not debilitating. This morning, my left eyelid felt heavy, but did not look any different in the mirror. A few hours later, I felt pressure around my left eye down to my left cheek bone. I will try to see a doctor tomorrow. By this evening, the pressure is still there and the symptoms are the same. 1. What could this be and should I be worried about it? 2. What questions should I ask the doctor? 3. Should I request an MRI?