My joints keep popping out of place.

This sounds exactly like Joint Hypermobility Sydrome. I have the same things...extreme range of motion in most of my joints, elbows and knees "bend backwards", and ALL my joints crack and pop all the time. Along with that is my joints disclocate really easily...especially my shoulder joints, usually while I'm sleeping. Go see a rhumetologist to rule out other connective tissue disorders like Ehlers-Danlos, and they will also likely refer you to a physical therapist.

@OP Not true! It is possible, though uncommon, to be short and have Marfan's. When I was diagnosed for it, I hadn't grown in years, I was 5'2 1/2". Now, I'm taller so, it's a different story. My mother has the gene for Marfan's and she is only 4'11".

my shoulder kept poppin outta joint years ago

throwin shit (and i useda pitch) fallin down and stretchin when wakin up once and it fuckin hurt

i stopped sleepin on my side with my arm outstretched where itd stress the joint

i gots a clue when i kept wakin up with that shoulder numb and cranked outta place

i stopped sleepin like that and aint hada problem since

not that thisll necessarily help yall but i thought id share

Talk to a doctor.

You may have a connectivity disorder, it could be something like Marfan's Syndrome or Ehlos Danlos Syndrome. For instance, I have the gene for Marfan's. I've had my muscles be both loose and rigid. My muscles are loose now, and occasionally, my joints will pop in and out, or I'll pull something and suffer a temporary injury. Once, I was talking and one side of my jaw popped out and got stuck. I couldn't move my mouth. I pushed on the part that popped out and it, thankfully, it went back in. I do recommend that you consult a doctor on this. There are health concerns that go hand in hand with connectivity disorders. Good luck. :)

Not normal, but I have this same problem and it sucks.
Usually its my shoulders. You may have hypermobility, which is a connective tissue symptom that could be caused from a number of possible conditions. You can easily tell if you have hypermobility if your joints bend in abnormal ways, although it can be hard to know what is abnormal when that is all you know. Compare your joint flexibility to your friends. Some cases of this, such as mine, get worse with age and can cause life long repeatitive injuries such as fractures, sprains and dislocations that get worse every time.