I have had this a couple times and it was hemorrhoids. The way you are describing it sounds much like that with the coming and going aspect. The two questions I would as is does it itch down there. That is a sign of hems and is it dark like swole said. They say dark is very bad. Ive had a colonoscopy when I was younger and its not as bad as you think, but you need to make sure it isn't something serious. Thinking positive thoughts wont help if its serious bro. Be careful. It could be something like gastritis and ulcer or several other things but blood work alone is not necessarily going to show it.







