Pain above naval on left side. Me.

I am feeling some discomfort on the left side of my stomach for past 15 days. Initially I was having continuous burps and small portion above naval on left side pains. I visited the doctor he gave medicines and said it's gas. But even after having medicine there was no relief so doctor ask me do sonography of abdomen and pelvis which was completely normal. I again visited other doctor even he said it's gas problem and gave some medicines. Right now the frequency of burps have reduced but on the left side above naval I am feeling that there is something which is pulling my muscles. I did CBC, thyroid, creatine test which is normal. I am not sure what is affecting my stomach. Request you to advice me that will give me 100% relief. I do not have any issues in toilet and urine it's just the stomach pain on the left side which is bothering me.