I also use earplugs for motorcycling. They get a minimum of 2 hours a day in the ears, and last holidays were regularly in my ears for over 10 hours a day. I use these
https://www.bunnings.com.au/protector-surefit-ear-plugs-canister-100-pack_p5820597 , which is an Australian reference. They fit my slightly narrower ear canals a bit easier than others.
I did get sore ears when using them for 10+ hours a day. It took about 6 days before they started to hurt, but then slowly became a full on ear ache needing pain killers. I asked my daughter (doctor) about it and she said that it was most likely caused by small amounts of grit getting on the ear plugs and hurting the inside of the ear canal as they were put in and pulled out. This causes the localised swelling. I had no infections, just inflammation.
Fresh ear plugs every time you use them will minimise this issue, but seems such a waste. I normally wait until they turn a bit "yuck" from my ear wax before throwing them out (about a week of usage).
I would suggest getting your ears checked for inflammation or infection, and maybe try other plugs from there if there is no infection.