Sounds like trapped surgical gas moving around from pumping up the belly from last surgery you had.When you worked out today you probably freed it up from where it was hiding.Mine is in my chest and shoulder.
During a laparoscopic surgery, CO2 is used to fill the abdomen and lift it away from the internal organs, giving the surgeon a better view for the procedure. Even though the CO2 is removed following surgery, the gas can become trapped against the diaphragm, causing pain and discomfort that can then radiate into the shoulder because of pressure on the phrenic nerve.
Heat and pain medications often bring relief. Try using two heating pads--one on the front and one on the back of the affected shoulder. If you are not taking medication for pain, ask your doctor which one might work best to alleviate your gas related pain.
Also for the shoulder pain, some hospitals recommend lying on your side and bringing your knees up to your chest. Hold this position for 5 to 15 minutes. As this can be difficult post hysterectomy, check with your doctor first. Lying on your back with your hips elevated on several pillows may also help.
To help dissipate the gas, consider peppermint tea, ginger ale, or carrot juice. Some doctors recommend drinking warm liquids. Carbonated drinks should be avoided for a few days.