Complex ovarian mass after hysterectomy

[nayade]

Hello, I would like to inquire about the following condition/situation. I am 38 years old and had a hysterectomy done two years ago in which they removed my uterus and left ovary. I had not experienced any problems until a couple of months ago in which I started to have pelvic and lower abdominal pain. From early test I was told that I had UTI and was treated with antibiotics, well the problem continued (the pain). I was finally sent for a sonogram, and after having had a transvaginal, I was told that I had a "complex right adnexal mass". My right ovary measures 5.2x4.7x4cm and this mass measures 4.8x3.8x4cm. They say that it contains considerable internal echoes and some fluid.
Now my question is, do cyst occur when a hysterectomy has been done, and are these masses things of concern. My doctor has told me to wait 5 weeks and have sono re-done again, but I'm leaning more towards having a second opinion....5 wks sounds like too long. Please advise. Thank you.