I had social anxiety and fear my entire life, but I also had situations how you describe without any fear but just didn't knew what to say and not being able to be interested in what other people are talking.
For some time now I try to be with people as much as I can, I almost never refuse and invitation to socializing. I noticed that as more as I did that the rare where the situation described above, so also without fear you can have social issues, so you need to hang out with people more.
Just try to find some environment to train in talking with other people, fail and again, fail and again... and so on... Without fear should be easy I would say, but maybe a bit boring