Chest tightness and burning sensation.

I am 18 year old male. I have chest tightness for about 6 months. I did ECG, ECO and even TMT, all are came normal. I did 4 ECG but nothing could be found by cardiologist. I feel some lump in my throat in esophagus region (neck region). Lipid profile was also normal. No Diabetes. No Thyroid Issue. LFT normal. I can also feel painful sensation when I inhale air from my mouth. I dont know whether it is cardiac related or Gastro related. The pain in the chest also spreads to back and also left hand. Used omeprazole tablet for a month but no use and also using Antacid immediately after every meal. Recently, a throat pain also developed now, It thinks it is esophagus region. No Stomach pain only chest pain especially in the throat area. Recently, I recently reduced 15 kgs in 5 months. There is no pain in the weight reduction period. I rarely eat one meal a day during the weightloss period. Did it anyhow cause any GERD or Esophagal Ulcer?