system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: what is actually happening when you get a "knot" in your muscle?

Edit: additional question...is massage the only solution? Or are there other ways to help them go back to normal?
gpt
Massage therapist here;

Your muscles are made up of bundles of long thin fibres. These bundles are wrapped in a very thin membrane (fascia). 

When you use the muscle a lot, the fibres stick together and to the membrane. Fibrous tissue feels "lumpy" and that's what you feel when you touch it. 

So it feels good when someone massages it, because it breaks up the fibrous tissue buildup.