Pain in the opening of anus. Like this.

This is embarrassing but I feel a small bud or outgrowth or a weird fold in skin in the opening on my anus. Generally it's painless when I poop but when I try to touch it to see what it it doesn't really hurt but I can feel it. But sometimes it gets swollen or something and the pain becomes noticable in daily life and while pooping. It's not exterme pain but it's a noticable one. Then this 'swelling' goes away withing 3-4 weeks and the pain goes away too and it goes back to the general situation I mentioned earlier. It's been over a year since I have noticed this and I thought it was anal fissure or hemorrhoids/piles but I don't want to be unsure about it. I have not experienced constipation but I used to experience bleeding like 6 months ago and haven't experienced that since then but the bleeding wasn't really painful. Please let me know what it could be or if it's serious or not because my mind imagines the worst case scenario when it comes to things like this. Thank you!