What Could Cause Slight Pain At The Base Of Tailbone Elevated While Flexing The Muscle To Cut Off Urination?

I have a slight pain at base of my spine/tailbone. It isn't very painful but I notice a sensation down there for the past 3 weeks. Feels like it's right at the base of my tailbone, right above the anus. It isn't a throbbing pain or anything, it only hurts at certain times. Also, you know the muscle or whatever you use to cut off your pee? When I sit straight and flex that muscle, that really seems to aggravate it. I ride a mountain bike a lot and the seat is narrow and not very comfortable and the tailbone pain I get from that is more painful but goes away after a day or so. I also started using a small foot stool when pooping about 3 months ago because I heard that is healthier for you. I am not sure what I did to cause this and if anything it is getting better but very slowly. I have no rectal bleeding and no pain or discomfort or constipation when pooping or peeing. Also, over the past 2 weeks I have been on vacation and have spent a lot of time on my couch playing games in a slouched position since my couch sucks. I am hoping this is caused from sitting too much and not something serious. I hope you can help, thanks.