Thank you for the additional information.
In medium to large breed dogs one common problem we see is a injury to the cruciate ligament in the knee and that can make them unwilling to get up and move around. This can happen so suddenly that often the owners do not notice. Click here for more on this
Some dogs when painful will tend to hide.
I asked about the neck and face because you mentioned vaccines and some dogs can have an immune system reaction due to vaccines and or coming in contact with areas that raccoons have been called coon hound paralysis and this can cause problem in the nerves of the legs and neck as well as the face, and can cause odd behavior as it effects the neurological system. This however will often cause a change in their bark and I apologize I did not ask about that. You can read more about this here
I can not say that the bumps are not from hitting her head but if she had some form of head trauma I would expect to see changes in the eyes or mental alertness both of which seem to be ok.
I would try to take a rectal temp just to be sure this is normal. Normal is 100.5-102.5 anything over 103.5 or under 100 requires immediate care.
As long as he temp is normal and the guns and tongue are not pale and she can move then I would watch her for the next 24 hours and see if she improves. If her bark changes, she becomes unable to walk or declines in any way then I would get her in to the vet to be checked. If she continues to favor that hind leg then I would be most suspicious of an injury to the knee.
I wish I could tell you for sure what was going on but she is not giving us any clear signs in one direction or the other.
Please keep me posted on how she is doing. I would try to keep her still for now and do not force her to get up other then to go potty. Bring her food and water in the bathroom if that is where she wants to be.
I hope she does ok. Please reply back if you have additional questions or concerns and I will be happy to continue.