What Could Cause Persistent Left-sided Head Pain, Excessive Sleepiness, And Memory Issues, And Are There Exercises Or Treatments To Help?

Hello,
I've issues regarding my head (brain). Mostly i feel pain on my left side of head, due to this I feel sleepy every time and not remember things for a long time.
I used to sleep 7 to hours daily but I always feel that it's not enough .
Kindly give a proper advise about this matter as well as any exercise.

Best Regards