I Took A Poop Yesterday That Was Especially Hard To

I took a poop yesterday that was especially hard to defecate, It took lots of intense pressure to get it to come out. Afterwards I now have a hard lump behind my rectum that was not there, it is tender and hurts but not real bad. I have hemorrhoids and usually keep them in check.. This is not a hemorrhoid. It is about an inch long and half wide with no idea on height as it is inside. It has been 24 hours and it is still there.. Hot water in the shower shrinks it but it came back.. Is it a stressed out muscle????