Random confirmation codes + people saying they have my “stolen lost phone”

I recently got my first cell phone. Ever since day 1 I’ve been getting random confirmation codes. These range from TikTok to Snapchat to Amazon, even though I had the app for neither. Not horrible, but annoying since I can’t verify my Snapchat phone number. One day, I get a text that says “yo i think someone sold me your lost phone” I don’t think it was a bot, and I talked a bit with the guy and he’s just like “that’s weird.” I brush it off but today I got another text with the same thing (differently worded). So I think someone’s using my phone number somehow? Any and all help is appreciated!