system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: what are muscle knots?

I was getting a back rub yesterday and my wife found a knot in my back that kept "clicking" when she would pass over it. What is it and what is the best way to get rid of them?
gpt
Muscle 'knots' or trigger points are a frequent discussion topic among health professionals and no one can really agree on what they are. 
There are a lot of conflicting opinions etc out there but we do know that muscle releasing techniques (massage/dry needling/acupuncture/foam rolling or using a spikey ball) can help alleviate any pain related to them. 
As for the clicking, that can be caused by rolling tendons or bands of muscle across each other or over a boney point/surface. 
It's normal for these to feel a bit sore when applying pressure to them so no need to be concerned or anything. 
Stretching and the other aforementioned methods are great for treating these 'knots'. However please don't try to dry needle or acupuncture yourself. 
That would be silly.