Volume goes up and down on its own

[XXI]

While watching YouTube my volume goes really low then it increases then the video pauses.

When I listen to my music it does the same thing except it doesn't pause on its own.

This started maybe a month ago and it's really annoying. Does anyone have a solution?

 

[j_hansen]

I noticed it happening a few time when using a bluetooth speaker that it would gradually increase sound but thought it was the speaker