I have multiple times a day a muscle popping sound, I'm sure it aren't my joints.
In my shoulder that happens involuntarily, I sometimes raise my arm and a high pitched snapping sound happens before being horizontal.
Also my muscles on the sides of my torso, if I place my hands in a triangle (against my hip) to the back and push down, it also happens and that one is the most troublesome cause it actually gives a burning sensation and is very loud but lower pitched popping sound, loud enough to that of a raised voice.
I suspect I sometimes get sleepy when there's the possibility to pop my torso muscles.
When that's done it's OK again.
Both also hurt a bit, but the shoulder doesn't burn at all.
I can do this everywhere with bigger muscle groups but these are the most troublesome.
What I want to know is, what is it exactly? Should I go to a doctor with it?
The fibers of the muscles, within the belly of the muscles, do not have the capability of popping or making sounds. Now, the tendons of the muscles can snap or pop over other tendons or bony prominences. It is very common to have snapping of the tendons around the hip and shoulder regions.
But, other than that, most of the sounds come from the joints. That sound is called benign crepitus. But, just like cracking your knuckles, it is not really known what causes the sound from the joints. In very specific cases, there is a known instability which allows the joints to sublux, then reduce with a clunk. Around the rib cage, the costochondral cartilage junctions sometimes will move and pop.
The burning sensation you get is from tweeking a nerve. One classic case of this is the so called "stinger" in the neck. Which can feel like someone placed a hot poker on the back of the neck/head.
If the incidences of the burning pain become frequent, then you might want to see your physician about it. But, usually it is just recommended that you don't voluntarily pop your joints or whatever it is that is causing the pain. If it is not done voluntary, then you will need to be evaluated as to why it is occurring.