Hidrosalpinx and Dermoid Cyst

Hello, I leave in Spain where we have a public health system. I developed quite a lot of pelvic pain, especially with pressure and went to the doctors here. The did an ultrasound and found the following: No right ovary (removed in surgery 11 years ago due to a large teratoma ), left ovary: 64x44mm with a cyst of 46x44mm wirh heterogenous and predominantly dense content, and hidrosalpinx on the LEFT falopian tube on the results sheets, I believe this might be a mistake as I remember the ultrasound technician telling me it was on the RIGHT falopian tube (translated from Spanish). The doctor has given me Encintyum 25 for the pain and said that i can either go for intervention now and remove the cyst or to redo the ultrasound in a few months to measure the cyst, which seemed very odd to me due to the discrepancy between them, but I chose the latter.
It left me with two worries: (a) the ultrasound tech said the image wan't that clear because I was on my period, (b) while the doctor gave me medicine for the pain (from the hidrosalpinx), he did not say what would be done about it, or if this medicine would also help with the more practical issues like really frequent and low volume urination (which i thought came from this and he agreed), and (c) given my past teratoma isn't it more likely that the cyst developes into something harmful?
I am therefore considering paying for a second ultraound (for clearer image) and a private doctor for a second opinion. Problem is it would be quite expensive (and I'm on a bartender salary). So I'd like to know whethher I'm being paranoid and it's ok to trust this doctor and take this pain medicine for a few months or if it's worth paying for a second opinion.

Thanks

Juli