Hello everyone,
I am a CRNA (certified registered nurse anesthetist). I can explain the shoulder pain to you.
First off the pain is not from anesthesia, its also not "gas pain" in the sense of intestinal pain.
The pain is referred from insufflation of the carbon dioxide used to inflate the abdomen for laproscopy. The nerve that becomes painful is the phrenic nerves. They originate in the 3rd, 4th and 5th cervicle vertabrae, make their way through the shoulder area and innervate the diaphragm. These are the main nerves that control the diahpragm, the major muscle of respiration. The phrenic nerves are exposed to the carbon dioxide during surgery.
The pain is not from pressure on the nerves from the insufflation but rather a chemical irratation of the nerves by the carbon dioxide. To put it simply the nerves send pain signals back up the nerves and the pain is referred to the shoulder.
The best thing for this is an intravenous/intramuscular NSAID called Toradol. Unfortunately unless they give this to you before you leave the hospital you are out of luck. The next best thing is Motrin in a prescription strength, which is 800mg. However, this may not work for everyone. The best thing to do is just rest, these nerves are located deep within your abdomen so heat/cold compresses are likely not to work. You basically have to wait until the nerve endings recover from the chemical irration of the carbon dioxide.
Feel free to ask your anesthesia provider about the Toradol before you go home. Aside from any contraindications I give Toradol to all my patients that under laparoscopic surgery.