Are there any anal receptive STDs that may cause intestinal discomfort, pain or cramps, or diarrhea?

Anal STDs. Any STD that can be transmitted through vaginal sex can be transmitted thru anal sex. HIV, around initial infection, can cause flu like symptoms. After anal sex, however, some ppl get a bit of diarrhea, cramping and GI pain. See ur doc to determine if you need a work up and review safe sex practices. .
Anal stds. Yes, all the ones we think about for vaginal diseases and penile diseases can cause infection in the lower GI tract in those who participate in anal receptive intercourse. You need to see a healthcare provider. Good luck.