My left shoulder has been hurting for a week. it hurts when i raise it above my head. especially put my hair up. i also struggle putting my jacket on if i need to get the arm behind my back. i dont recall any injuries to it. help please?

You probably has mild rotator cuff injury which is quite common. You can take Ibuprofen OTC 200 mg x 3 tablets every 6-8 hours as needed for 2-3 days (take with full stomach) and avoid the activity which exacerbate the symptoms during that time frame. When the pain eases, you can slowly resume the normal activity. If pain persists or get worse, you should see an orthopedist.