A: It is always a good idea to have a child with a limp and no known injury checked by a physician if it lasts more than a few days as most likley it will be nothing serious but rarely it can be the presenting symptom of leukemia. It could also be a sign of a viral or bacterial infection of the hip joint. Bumps in the groin may be lumph nodes especially if the child has had any sores on his legs in the past few days or they could be inguinal hernias, athough it would be less likely if they both suddenly appeared and no one has ever noticed them in the past. The other possibility is that his testicles may be retractile and that is what you are feeling in his groin. Check and see if you can feel them in his scrotal sac and if you can not that may be the bumps you are feeling.