There are , many conditons , which can cause these symptoms. You need clinical checkup from Surgeon. It can be due to-skin tags, rectal tags,Haemorrhoids, Prostate condition,
it is very difficult to diagnose, without clinical examination. My advice is that clinical examination from surgeon, to evaluate the cause, Treatment will be done accordingly after diagnosis.
Sourcehttp://cureresearch.com/sym/rectal_lump.htm#possible
I hope this has helped.