My MRI results: Mildly heterogeneous myometrial echotexture without a well circumscribed mass. Could this explain my abdominal and lower back pain?
Probably not. It may be within normal range, difficult to assess without the images and the description of "mildly" heterogeneous echotexture. Also, that is an ultrasound description of findings, not MRI. Which did you have?
Fibroids/adenomyosis. The two most common causes of a heterogenous uterus are uterine fibroids, which are benign muscular growths in the uterine wall, and adenomyosis, which is a proliferation of the normal uterine glands into the muscular wall of the uterus. Both of these conditions are benign (in the cancer sense) but can cause pain and gynaecologic symptoms.
NO. get a PT evaluation and an arthritic workup.
Pelvic MRI. Here are some general comments on purpose of a pelvic MRI: https://medlineplus.gov/ency/article/007355.htm For a specific interpretation and whether an answer has been found re your pain please consult the doctor who ordered this test for you or a gynaecologist licensed in your area as there are a variety of possibilities here.