I just recently started hearing water in my bathroom water . Sometimes it sounds like a running toilet . I hope its not a major problem and I just never noticed . Any ideas ?

Why did you title your question 'Radiator?' If your radiator is making sounds, please say what kind, and what kind of heating system you have.

I sometimes hear water in the bathroom too, in the morning. I finally decided that snow/ice on the top of the stack for both the bathroom and kitchen was on top of a few leaves clogging the top of the pipe out the roof.
When the sun hits it, it melts and gurgles as it drips down into the cellar drain.
I have no proof but I think it was a brilliant bit of guesswork, LOL.

Toilet? "Hearing water in my bathroom water... closet??".