i remember near the end of my pregnancy i felt more discomfort too and not so much movement.
remember that now the baby is pretty much almost due to come out, and has grown alot, so there is not much space in your uterus for him or her to move and kick around.
if you feel unsure if this is ok or not, i would give your doctor or OB a call and see what he or she thinks, and if you should come in.

I remember it being extremely uncomfortable in my last few weeks, i was sleeping on the couch instead of the bed to put my leg up more for comfort, and walking was hard to do because my back would hurt.
i felt less movement at the end, and had uncomfortable cramping.
its almost time for your baby to be born, you have 4 more weeks so things will not be a comfy as before.
if there is no bleeding with the cramps they are fine, this is what my doctor and sister inlaw who is a nure told me, but again, if you are still unsure give the doctor a call.

also you could try drinking a glass of cold water and relaxing on the couch to see if your baby moves around. i did that a few times and my baby would move.

hope that was helpful.