I have a concern about this cough i have been having for?

like more than 3 months no flu symptoms no phlegm or mucus and i was told by the doctor at the er that it was upper respiratory infection and took v-pack for 10 days and it kind of helped then it came back with the cough its up in the right chest area near the throat but more to the right were the bone is its like a tickle in there and its so annoying i had chest x-rays and blood work and they did a ekg and everything was fine even my respiration was in the high 98-100 so that was good but the right side of my upper lung area is that annoying tickle and cough i've had bronchitis in the ped but they didn't mention that at all what do you think it could be thanks for your help..