Maybe the accident changed your gait and you've put too much pressure on part of the joint? Or soft tissue damage? Or trapped nerve? Does it feel like a bone pain, muscle/ ligament pain or a sharp nerve pain?
Definitely not an accident or an emergency though, and they won't be able to give you answers anyway even if you did go.
If the pain is controlled by over the counter ibroprufen then it doesn't sound like a big problem to be honest.
With numbness needs checking out though, and I can understand why you'd be scared. All those bad body memories come flooding back.
If it becomes a constant problem (vs a scary one off) I'd be pushing for a referral as your gp won't be able to examine what's happening inside, and it's easy to end up with an assumption for a diagnosis.
One of my muscles went into hyperdrive (due to a complicated reason thats not relevant here!) and did the work of many other (bigger) muscles, so pulled my leg forwards in the hip socket so I couldn't lift up my leg without the hip joint stopping the bone from moving. That in turn caused trapped nerves and further messed up my walking. By the time I saw someone that could work out what was going on, I couldn't walk at all! So weird things can happen to bits of the body that seem quite simple.
My gp at the time fobbed me off for over 18 mths until I couldn't walk at all, I changed gps and the new one was horror struck that I'd got to the point of being immobile without any expert seeing me or intervention. So my advice is, don't panic, and if it is recurring or getting worse, be that squeaky wheel to get help.