1 month ago i was told i had infection & serous otitis media in my left ear and ringing but now my right ear is also ringing iv been on 2 anti biotics?

Same thing: With a middle ear infection, there is fluid in the middle ear, so when the infection clears, the fluid has to drain from the eustachian tube. It is likely that the right ear developed an effusion(fluid) in the middle ear, as well. When this occurs, it is common to hear ringing. Antibiotics are not likely of benefit. Decongestants & other rx may be needed. When the fluid clears, symptoms improve.

Ear Infection RIng: Serous otitis medial is generally associated with blockage in the eustachian tube, the opening between the middle ear and back of the nose. Ringing is often associated with hearing loss. Try gently clearing your ears by closing your mouth, and blowing your nose. The ears should pop or feel full. If they don't clear, i feel the best course is a short round of inhaled nasal steroid or oral steroids.