Welcome and thank you to HCM
From your description you are probably having conjunctivitis
which is usually caused by infections such as virus, bacteria, fungal or mycobacterium
etc and could as a result of allergies, order underlying systemic diseases eetc Diagnosis of the affection is clinical and you will require steroid
and antibacterial eye drops to ease the pain and treat the cause. If these do not work, then you will need to visit an ophthalmologist as soon as possible.
Hope this helps