The commonest cause of hydrosalpinx is infections like chlamydia, gonorrhoea or genital tuberculosis
which is probably your case too. Rarer causes include hematosalpinx
or tumors. It might be advisable to ask you radiologist
if there was free peritoneal spill on the right side since this would tell you the patency of the tube as well as may be a pointer to pelvic inflammatory disease
The cystic lesion you mentioned (in 2010) may have been an ovarian cyst which later disappeared. The hydrosalpinx maybe a new problem. Hydrosalpinx maybe treated with medications or by tubal corrective surgery (if it persisits) but this may also not achieve very good post surgical conception rates and also carries a small risk of ectopic pregnancy. Recurrence is usually not a consideration. Since the other tube is patent, there probably shouldn't be any problem with conception.
It is advisable to meet a gynaecologist with experience in infertility treatment
for further evaluation and plan of management.