Breathing Problem. And future treatment.

I am having breathing problem (heavy/ laboured breathing) and feel very lethargic all day since last 4 months. I have got Troponin test, Stress Echo, Chest X-ray and ultrasound done with all ok reports. Also, got PFT done wherein I was able to inhale properly but couldn’t exhale completely. Got blood and urine test done and all clinical parameters are all ok except the following: Bilirubin : 1.99 mg/dL, however SGOT/SGPT are ok Vitamin-D:55 nmol/ L Vitamin B-12: 177 pg/mL Apo A1: 95 mg/dL Apo B: 37 mg/dL Also, have a persistent feeling of something getting pulled in the middle of the stomach (between both ribs). Have consulted a cardiologist, pulmonologist, radiologist, Gastroenterologist as well but the problem still persists. Taking Tolol XR25 OD for last few years for high BP. Have taken gastritis medicines like Pantakind DSR/ Zecid 20 mg for last 10-20-30 days as advised by the physician but it didn't help. Pls advice what could be problem and future treatment.