I think I know tbh, but don't want to jump to conclusions
Pain at backs of thighs and inner thighs (have great difficulty opening legs very far) and legs feel very heavy, can happen after doing a bit of walking, or just sitting somewhere for a while.
Is this SPD or just pain it does not feel normal, should add legs also feel very stiff when moving them. Can't walk very far without really suffering after 10-15 mins.
Second pregnancy, am 35+2. Did not have this sort of thing when pregnant with DD.