Legs burning

So yesterday i worked out with my little brother we did a bunch of leg stuff and i was feeling fine then today when i wake up this morning my thighs started to hurt it hurt when i sit down and stand up, it hurts when i walk so i told my mom that my thighs were hurting and she said that's because your bones are getting old once it starts to rain that's when arthritis happens i don't think its arthritis im only 19 however she told me to put icy hot on it and i did but it didn't work and after a while it started to burn so i washed it off and now my legs are burning and they still hurt help😢