Dry + small wet Cough from last 2.

I was down with cough issue from last almost two and half months and meanwhile I visited to three different doctors. But nothing worked major. I had done my cbc test ,urine cluture and chest x ray test, the reports were normal. One month ago I visited one more doctor and told him about my cough issue, he gave me some medicine in three visits to him, following which I observed major improvement in my coughing but still I feel something like belgum or cough is stuck inside my throat. To clear this I have to cough. sometimes my nose blocked ,sometime i fell like my throat is good  sometimes is looks not  Is this is viral fever as all doc told me??? Or something major?? I don't know why is it happening to me from last three months. I am into depression because of this. It's very irritating. Please suggest me doctor what to do now. I am tired of taking medicines. (PS: In my previous visits to doctors I visited to 2 MBBS, 1 BHMS and 1 general physician)