Answer:
First off make sure that the crutches are long enough..it hurts more if they are not lengthened enough
Are your underarms sore? You can get new cushions if they are worn down..if you must walk a lot you can shift weight to the hand cushions for a bit as you walk along\
Be sure to take small steps and take your time and dont hurry Stop once in a while to give your arms a rest
Also , try to use your arms to swing your body rather then your underarms .