Can't tell if he was flirting or not

I (26F) have a lot of trouble telling when men are flirting with me or not, especially older guys. The other day I was talking to a male friend of mine (34M) about something that was causing me great distress and sadness. He was super understanding and supportive and after a while started rubbing my back while I was talking to him. I thought that was sweet of him and that he was trying to comfort me. However, after we changed the subject and we started talking about random stuff, he kept on doing that... We were telling each other funny things and jokes and he would constantly reach out his hand to caress my back hours later that day. He did this multible times... like 8 or 9 times.

Please enlighten me, is this generally considered flirting or is this just being comforting because I had a rough day? We also have a bit of an age gap, so maybe this was more like a "big brother" thing of him to do? I also didn't want to straight up ask him "are you flirting with me right now?" in fear it might ruin our friendship