Uterine fibroids are extremely common and almost always benign. According to the U.S. Office on Women's Health only about 1 in 1000 are cancerous. Yours is small. 3.4cm is less then 1-1/2 inches. Fibroids don't always cause symptoms but when they do, one of the most common is heavy or irregular bleeding. I don't think pain is typical especially for a fibroid this small so it's possible something else is causing the pain.
Unfortunately, many women end up having a hysterectomy for fibroids or other benign conditions. The problem with that is it trades one set of (temporary) problems for a whole other set (of permanent problems). There are less drastic options that preserve the uterus and its LIFELONG non-reproductive functions.
Best of luck to you in getting answers and proper treatment!