I'm 45. I found a very hard lump just underneath the skin on the left side of the sphincter of my anus. It feels painless unless I compress it and often in certain positions I feel a little discomfort. I have been to the docs and was told it's a hemorrhoid, in fact I have two, but even though he examined me he did not feel the lump at all, just looked. Last week there was a purplish bruising adjacent to my anus about a centimetre away from the lump, but that has subsided now, leaving just this incredibly hard lump, unchanged in size still in the same place.

There is no blood during bowel movements. 

I have suffered from anal itching for most of my life, so I have been aware of the landscape of my anatomy. This lump must have appeared quickly, but it has not grown any larger since I first discovered it.

As I've been to the doctor and he has diagnosed hemorrhoids I am relatively sure, but I have this worry in the fact that it is so hard, and I'm unsure if I should just accept his word on this. 

What do you suggest?