Hi, I have a problem with hemorrhoids, and I really really need somebody's opinion.

About two years ago I had an anal fissure that needed nitroglycerin to heal. It was intensely painful, and really impacted my life. I got it after a night out drinking. Determined to never have another problem down under, I quit drinking, upped my daily fiber and fluids and try to maintain regularity. Earlier this year though, I began to have hemorrhoids, and they are awful. I have no idea what set them off, or why, but I have had 4 within the last 4 months, all of them in different spots

I've been to three doctors, and all of them tell me "it's just one of those things. Some people just get hemorrhoids", but I don't buy it. Why would they suddenly just start appearing like this, and so many in such a close frequency? Does anybody know of any other risk factors and reasons why someone gets hemorrhoids other than straining, being overweight, sedentary lifestyle, inadequate fiber, etc...?

I am male, 28, heterosexual, about 140 pounds (6 feet even), I ride my bike to get around town usually getting about 20-30 miles a day, I am a vegetarian following a high fiber diet and I get more than enough fluid. But they keep coming. The latest one, I woke up with in the morning, after a normal day with normal bowel movements the day before.

I'm starting to get really worried about this. It's taking over my life. Any help would be greatly appreciated.