I have pulmonary hypertention and i am having rectal bleeding the last couple days it's happening more frequent and on its own. what could it be?

Prob not related: I don't know of a direct connection with rectal bleeding and pulmonary hypertension. If you are taking any blood thinners including Aspirin this can increase your risk of GI bleeding (gastrointestinal -esophagus to anus). Either way you need to see a doctor asap. Increasing bleeding needs to be figured out and treated. Don't delay.

See your doctor: The usual reasons for rectal bleeding - anal fissure, polyp, vascular malformation, ulceration, hemorrhoid. However, if you are taking epoprostenol (flolan) for your pulmonary hypertension - with reports of increased bleeding, presumably due to the effect of the drug on platelet function (platelets help stop bleeding). See your doctor in any case for further testing and possible change in rx.