Unexplained leg pain in a 4 yr old for over 2 yrs.

[awelch81]

My 4 yr old son has been having leg pain for over 2 yrs.  He experiences this pain several times a week and until the last few months was only at night.  Recently he began to have problems during the day.  He couldn't stand up yesterday and when I made him try he would fall to the ground and cry.  This lasted a couple of hours and then he seemed to be okay, but I still took him to our pediatrician.  They did some blood work and are going to send us to a bone specialist.  What could this be??  For so long I've been told that it is growing pains and just to give him motrin.  I have gotten into the routine of doing this and rubbing his feet and legs until it passes.  No one ever said thai it could be anything more until now.  Is low potassium a possibility??  I'm worried.  His doctor tested him for Lupus, arthritis, and she did a sed rate.  

[forkumd]

Does he get headaches when he coughs or cries?

[TJB16]

Have the doctors ck the hips. My son was recently diagnosed with legg perthes disease its a hip problem usually pain in the leggs knee upper thighs.The shape of the hip bone is not round as it should be. The doc's think with my son it will heal it may take along time.my son is in alot of pain. We were told to give motrin as well we have some very bad days especially if he's been really active. Good Luck!!!