Hi and welcome to Healthcare magic.Thank you for the query.
I am not sure these t2 are related but this bump can indicate perianal abscess
and it should be treated by surgeon. Your abdominal symptoms should be evaluated by endoscopic tests, not ultrasound
,because US isnt specific enough. There can be stomach or bowel disorder and most common are gastritis
issue and IBD.
Wish you good health. Regards