Can arimidex (anastrozole) cause shooting pains in the groin area & backside?

Yes. Please see your doctor or call them immediately- this is one of those things that they like to hear about quickly.
Possible. The major side effect i hear as a surgeon is the pt. Complaining of aches -mild pains- cramps in the thigh muscles primarily or second - around the hip joint - so that it is hard to stand up, get on/off my exam table, or off the toilet or climb stairs. Shooting pains is rare - making me think first of radiating pain from the lumbar spine - sciatica- possible L2 L3 or rarely direct bone involveme.