Most commonly the pain from an SI joint dysfunction is either directly over the SI joint itself or may radiate pain lower down into the buttocks. The pain may affect one side or both SI joints. Most times the pain from an irritable SI joint remains well above the knee, but in a few cases it can radiate down the leg all the way to the foot and may be confused with a herniated disc of the lumbar spine. The pain may also radiate into the groin area. People often feel muscle spasm or tightness in one or both of their buttocks muscles when the SI joint is affected.
Problems with the SI joint may make sitting difficult. Pain in one SI joint may cause a person to sit with that buttock tilted up as it is often uncomfortable to sit flat in a chair. Walking can also be very painful depending on the degree of irritability of the joint and whether or not the joint is considered to have too much movement or is deemed stiff. Increased motion at the joint, such as during pregnancy, can be a particularly debilitating problem which makes activities such as going up or down stairs, standing on one leg, putting on your shoes and socks, or getting in and out of a car difficult. Turning over in bed is also particularly difficult when the SI joint moves more than normal.