Difficulty in swallowing. Khatta aam.

Ti sir, 3 months back while doing warm salt gargle I drink some amount of salt water. Suddenly I got throat pain and my voice got low for some time. I went to ent doctor he prescribed some medicine and mentioned as throat burn due to URI (Upper respiratory infections). I took medicine for 7 days but no improvement. Then I went to my family doctor and he told it's an ulcer and he prescribed betadine gargle for 3 days. Next day my brothers 4 years old son suddenly pressed my throat and it pain for 30 minutes and some liquid type felt in my throat. My family dr sent me to ENT specialist he insert one thin rod and checked in his screen and told there is nothing serious and he asked me to take mucaine gel syrup two times daily. I have consulted 2-3 ENT doctors and did USG, barium swallow and CT scan with contrast but all came normal. Two times I got cured but after eating khatta aam again I got throat pain. So pls guide what was wrong with khatta aam.