Hi, i have constant ringing in my right ear for about 4 years at the least. i also have mild sinus. doctors here don't seem to believe me. please help?

Get it seen: Does need an examination. Not sure what you mean by doctors don't believe you. Might want to try seeing another one as without seeing you it's not clear whether this is ear infection sinus problem migraine or other cause.

Tinnitus: Tinnitus (TIN-ih-tus) is the perception of noise or ringing in the ears. A common problem, tinnitus affects about 1 in 5 people. Tinnitus isn't a condition itself — it's a symptom of an underlying condition, such as age-related hearing loss, ear injury or a circulatory system disorder. http://www.mayoclinic.org/diseases-conditions/tinnitus/home/ovc-20180349

Chronic tinnitus: Do you have a history of loud noise exposure? Have you had your hearing tested by an audiologist? Probably the most common cause of tinnitus (ringing in the ears) is age-related hearing loss. Past exposure to certain medications can also cause tinnitus. You can read more about it here: http://www.mayoclinic.org/diseases-conditions/tinnitus/symptoms-causes/dxc-20180362