Did some looking up of SPD yesterday after talking to the MW and found this - might be useful for you MotherofZ and Mixedmama (sorry if it wasn't you guys who were feeling sore too). I have to say it describes the discomfort/pain I have been getting exactly and also where I have been getting it. I assumed it wasn't SPD before as it was not just in my hips but that seems normal.
"The most common symptom is pain and difficulty when walking. Some women describe the feeling of their pelvis coming apart. The pain is made worse when turning in bed or doing something that involves standing on one leg, such as climbing up stairs, getting dressed and getting in and out of a car."
"The pain is generally felt in the pubis and/or the sacro-iliac joints, but can also be experienced in the groin, the inner side of the thighs, the hips and in one or both buttocks."