When you resume training the powerlifts, use moderate poundages and ease back into training. Some initial soreness after a layoff is inevitable. If you find that you require layoffs frequently or have joint or muscle soreness regularly, then re-evaluate your training. You may be overtraining. Too many novice powerlifters train in a 'bodybuilder's fashion,' that is massive quantities of sets and reps.
Quality is the key to a powerlifting program.
Most of the routines used by top lifters consist of low amounts of sets and reps, but the training is high quality. The big weights add up on the body much faster than lighter, higher volume work. Leave the pumping to the bodybuilders. Limit your contests to three to six meets per year with some coming within a few weeks of each other. Lifters who are constantly competing will soon burn out.