What Causes Constant Headache?

im a 25 year old female. i have had a constant headache for 9 days. it is around my eyes and nose and alternates between my right and left side. most of the time its a dull pain, but sometimes its sharper. it feels like its itching/tingling. i am waiting on my bar results to get back and planning a wedding. i was studying for 2 months on the computer for 8-10 hours a day. i dont exercise and watch tv alot. i stopped smoking because i think its a trigger. this headache makes me really nervous and i cant sleep and i get dizzy and feel like i cant breathe and my heart beats really fast. i also have shoulder/neck pain on my left side and weakness in my left arm. i clench and grind my teeth. i dont wear my glasses like i should. what is wrong with me?