Carrying something heavy on one shoulder
“When you carry heavy bags on one side, you disturb the angle of your neck, and it can cause pressure on the nerves that come between the vertebrae in the neck and provide sensation to the arms,” Dr. South-Paul says.
“If there is pressure on the nerves as they exit the neck, one can experience numbness, tingling, and even pain in the shoulders and arms.” So, to have a clue about how much your bag can weight, the American Chiropractic Association says that it can weight no more than 10 percent of your body weight.
