This is indeed a common experience, and the reasons why could be many. It may have to do with the direction that threat came from, or if the stressor or ‘bad thing’ was associated more with the left or right side of the brain. It may also have to do with postural dynamics, or repetitive motions. No matter the cause, noticing differences and moving our attention back and forth between those different experiences is a way that we will often work with expressions of held trauma, so oftentimes it can be a gift that one side may feel less stressed than the other, and overt time we tend to see the two sides equalize – where the side that was more stressed relaxes, and/or the side where we may have felt very little starts to have new sensations.