Was seen for dub and pelvic pain by gyn, had a us done on day 28 endometrium is 11mm thick i have 40day cycles is it normal? trying to conceive

No: Cycles normally run from 21-35 days. A cycle that runs every 40 days is usually a sign that you are not ovulating normally. This can be caused by many factors but by not ovulating normally you can give you difficulty getting pregnant. I would suggest doing basal body temp charts or ovulation tests to see when you are ovulating, and if not ovulating you will need assistance from your gyn.