apart from following the advice of dr mittal and dr rajan .you can get your  allergy testing done. you can also observe ,that by which  things the allergy starts or increase.  and after identifying the cause  you can easily avoid that.

Hello Try A.cold compresses B avoid rubbing eyes C avoid exposure to dust D use antiallergic eyedrop like epinastine eyedrop along with lubricating lubricating eyedrop frequently E.  Soft steroid like fluorometholone can be used in pulse dose in severe cases Having said that it is provisional diagnosis Kindly share photos of your eye so that I may guide you better Regards

Sounds like u have allergic conjujnctivitis. Applying ice pack over ur eye should give u some relief from itching. There is no pain killer available for this condition, but u can apply Mast cell stabilisers like olopatadine for around 2-3 months. Along with this u can use mild steriods like Loteprednol for short periods of time for relief. But these have to be used under the guidance of an eye doctor.