If you have fibromyalgia the muscles in your abdomen will set up trigger points (TrPs) if an internal organ is problematic. Abdominal muscle TrPs can cause internal organ problems and set of a cycle of re-enforcing referred pain. They can produce projectile vomiting, anorexia, nausea, bloating, burning fullness, and a host of other problems. You can massage these TrPs to get some partial relief at least.
If the bowel is blocked you will be extremely constipated. Lying flat on the floor with a cushion under your belly MAY help. Also try lying on your side knees to chest.
If your biliary system is congested you will have pale stools; light cardboard. Gastro paresis (slow stomach emptying) is also related to Gallstones blocking a duct. If your stools are grey coloured then the main bile duct is blocked. You can take a tablespoon of Epsom Salts in a glass of warm (room temp) water on an empty stomach. If the pain is reduced you know you have a blocked, obstructed of congested bile duct.