Can thrush cause swelling under urethra? No problems with passing urine, came off microgynon 2 weeks ago, abdominal pain around ovaries.

Possibly. A severe yeast/fungal/candida vaginitis (thrush) certainly can cause redness, tenderness, and swelling in the region of the urethra. If however, you feel an abnormality or "lump" underneath the urethra, that suggests a different type of problem (e.g. Skene's duct cyst or urethral diverticulum) and a pelvic exam would diagnose, .