Lower left abdomen burning sensation

[kimono1803]

For the last 1 month, I have been having the following issues
1. Gastric trouble (burping, passing wind)
2. Burning sensation in the middle of the chest and to the left side of the chest (feels like heartburn)
3. Undigested food in the stools occasionally
4. Burning sensation in the lower left abdomen (1 inch below the navel, and 2 inches to the left of it), normally there is no pain in this area, the skin when rubbed has a sore/burning sensation, and on pressing that area, I have a slight discomfort. On lying down and stretching, the muscles seem to cause some pain

I really want to know what the issue is, please help. I also want to rule out any reproductive organ issue(My pelvic and abdominal Ultrasound looks good without any issues, the general health checkup is also fine, and the thyroid values are also normal).
Is it something related to gas only?

[kimono1803]

The burning sensation also goes down to the left pubic area. This is not there on all the days, it comes and goes on and off. This is really eating my head, The stool test has come out normal, and the urine test also. Please some one help me narrow down the issue

[kimono1803]

I am 28/female and also have allergic rhinitis. The last 3-4 months have also been pretty stressful for me. Could this add to the symptoms?