Hi,It is very difficult to diagnose your problem without knowing following,
1-Age & sex of patient.
2-Associated problems like
vomiting,headache,etc.
3-any other problems in eyes like
redness,watering,discharge etc.
At this time I can only say that you may be suffering from either of the following
diseases,
Glaucoma,
Iritis,Migrain,Herpes&May be some space occupying leision.......
With out knowing these factors I can't suggest any treatment And investigations.
This is all What I could comment .