Sharp Pain in my head after light exersion

About 2 weeks ago, I was tying my laces and when I came up I banged the back of my head pretty hard on a metal railing which I didnt see was there (swole up a bit, put ice on it when I got home). Forward about a week later I moved into a new apartment this involved alot of heavy lifting, couple of days later I got a real bad migraine, I'm talking a 9.5 on a scale of 1-10, felt like my brain was splitting into two. I took night time tyneol and woke up with the pain in my head about a 7. it's been going on and off since, I notice it comes when I exert my self, I felt it coming on during my weight lifting workout last week. It's a sharp pain feels like its piercing.

I have a small history of migraines, when i was about 15 I used to get random migraines which lasted about 3 hours, I noticed light intensity reduced the pain, now I dont know what is causing it. I''m not even sure if the banging of the head is related to it. I wake up in alot of pain, head and back.

BTW, now I'm 21.