Understanding Unusual Body Sensations: What Could It Be?

It is not likely related to your blood. Bubbles cannot form or pop inside of your blood vessels, and any changes in your blood would typically require a medical diagnosis.

The sensations you are describing are more likely related to natural muscle movements, the release of endorphins, or perhaps even muscle twitches associated with stress or anxiety. These phenomena are usually harmless, but I recommend speaking with a medical professional if you continue to have persistent concerns about any physical sensations you experience.