normal pap smear, no cyst on ovaries, obgyn wants to do a d&c????

so I went to the Dr to get a pap done... results came back normal. a week later he sent me for a transvaginal ultrasound & less than 5 days later I had my consult with him... he said my ovaries looked fine, no cyst, but my endometrial lining is really thick?? I was like uhmm? ok? he didn't want to do a biopsy he jumped straight to the chase about being put under & having a D&C; done to clear whatever it is all out? isn't there medicine I can take instead? anybody ever have this happen? I'm nervous & I have been trying for 3 years & I haven't gotten pregnant....