I have pcos and ovulate on clomid (clomiphene) 50g. i have not had any lost pregnancy. my re ordered hysterosonogram test. is it really required?

Yes: The hsg will check for open fallopian tubes and intra-uterine "structural" abnormalities. It is very hard to get pregnant even if ovulating, if the "tunnel of love"(fallopian tubes) are blocked.

Probably: If you are ovulating with Clomid (clomiphene) and have not conceived after 3 or 4 ovulatory cycles, it would be appropriate to evaluate for other infertility causes such as tubal occlusion. The hsg would answer that question. You should also have your partner tested with a semen analysis, if that has not been done.