hip replaced March 20th, leg and knee pain still there. Is this normal?

It wss really hard for me to find information on this. Most patients are 80% recovered by six weeks. Since its been 12 weeks for you and the pain is apparently still pretty high then you are not like 'most patients'. On the other hand I found reports indicating that recovery rates are 'very variable' with significant swelling still present 3-6 months later. 

I imagine your concern is if something is really wrong and I wish I could help you with that. Lingering infections can cause pain, if the replacement is not seated correctly that can cause pain, if there was nerve damage in there either present before the surgery or was caused by the surgery - that can cause pain. Or you could just be slowly healing. People heal at different rates following major surgeries.  I know someone who had knee replacement who was in horrific pain for several months afterwards. Other people have very few problems with pain. 

The best thing I can think to do is to keep telling your physician how it's going and to prod him/her for answers if it doesn't get better. Good luck!