Is it normal for some people to talk to me way too much?

My friend's mom, A, talks way too much. I can't stand it. When I'm at my friend's house, B, A delivers her monologues to me for like 15 minutes, and I can't do anything about it. I have to sit and suffer through it. A's monologues are always about stupid stuff that I don't care about. A's always complaining about stupid stuff, mostly B. She goes on and on about how irresponsible B is. And sometimes she does it while we're watching a movie at B's house. It's so annoying because then I can't watch the movie. I wish I could tell A to shut up, but I can't. And sometimes A calls me on my phone and won't shut up. I barely even say anything during her monologues because she talks nonstop. Tonight she was so annoying. I was in the shower at 10 pm and I heard my phone ringing so I got out and answered it. It was A and she talked for 10 minutes. I have other things to do besides listen to A go on and on all night. A asked if I knew where B was because she was worried. A said that B met a guy online who B doesn't know and was with him today and they went to a movie but B won't answer her phone for A. I said I didn't know where B was at the beginning of the call but A still kept going on and on. I wish A would leave me alone.