Welcome to health care magic!
I have gone through your question carefully, from that the main point is that your forehead aches when you try to look something upwards, by rolling your eye balls upside, now you have stared having headaches
From my clinical experince I feel that you should go and consult a doctor. Had I been treating you I would go for an MRI
Brain to rule out any neurological cause for this. It would be fine to get an X Ray
neck done and see if there is cervical cause related.
Nowhere you have mentioned that you have any visual problems, but one can go for measuring the intraocular pressure
. Normal vision largely rules out any cause related to your eyes.
Main advice will be not to neglect this problem and visit a doctor and get yourself adequately investigated. Till then avoid making that particular movement, and for pain I feel that diclofenac
50mg will give relief.
Hope the answer helps you in getting better.
Feel free to ask more if you need clarifications.