What are some common injuries and pain problems experienced by our current service members?

Ortho must be the most common; carrying weight and impact from jumps is rough on joints..
Me personally? I sound like rice crispies (snap cackle pop) all the time, especially in the morning, and ignore ortho and lower back pain most of every day.
5 long deployments in and 7 short tours? Some lung and GI issues prop up periodically, and every now and then, I talk to a friend or professional about the harder shit I've done and seen.
I don't think anyone does what we do for a long time and comes out the other side without some medical issues.
My advice is: man up, and know that none of us does anything without help. Seek medical and psychological help early and often. Don't be empressed by a sprained abkle, don't be embarrassed by having trouble moving past a mission or patient. Ask for help. We don't conduct a patrol by ourselves, don't go through repercussions by yourself. No one is really embarrassed about getting shot, don't be embarrassed by other injuries.
Get yourself fixed up, you can serve longer, in or out of uniform; take care of yourself so you can take care of your country.

All of them.

Sprains, knee, foot, back, and hip issues.