Hi for past 5 months i have a sore throat and mri revealed cyst in right maxillary sinus.can this be the cause? throat always have little pain

Not likely: Even though you might have a cyst in the sinus it will probably not cause a sore throat. The cyst should be seen by an ENT or oral surgeon but is likely to not be related.

Unlikely : A sore throat for 5 months suggests chronic stimulation from allergens or irritants and or mouth breathing to bypass nasal obstruction. A maxillary cyst suggests prior, not new, allergic and or infectious changes. A review with exam can help sort through the issue.