Left side Chest and back pain, heartburn

For almost a year now, I have a constant mild pain in left side of chest and at the left back. Not sure whether back pain radiates to the front or vice versa. Sometimes the pain is uncomfortable and sometimes it's barely noticeable. Went to doctor recently. As I'm overweight doctor suggested ecg & echo test. For which results were normal. Doctor said might be due to stress. So I can't figure out at my 1st visit what causes this constant chest & back pain. Also frequently have heartburn as soon as I have food. Eating oily foods or sweets cause indigestion and oily stools. This wasn't the case before. I've assumed it's because of poor diet in lockdown and started to change my lifestyle. But parents are worried and thinking of cancers, tumours. I don't think the pain is that serious. Recent blood tests had all values normal except vitamin D(low), Fructosamine(High) & the two values attached below. Kindly suggest any other tests to be taken and which specialization should I approach.