In my experience, treat Ur gastric issue first - U can take more fibers, veggies, fruits. Move regularly, drink plenty of water, avoid prolong sitting in one position. You can also do some clockwise anticlockwise massage at Ur abdominal region, regular bowel movements are a must. Do not hold your urination or bowel, whenever you have urge plz remember to empty yourself.
Once your gastric issue is better, your neck and shoulder pain should reduce tremendously. Also remember to do some stretching exercises and make some ergonomic changes for your office environment.
Next Steps
Movement are necessary.
Health Tips
U can go for swimming or walking