During playing? I hit pretty hard. Sometimes it just goes over and I get a twinge (sharp pain) that lasts for a second, or if I hit a hard stroke out of position I get a twinge then too. This doesn't last, my arms and shoulders feel fine after play.
in my opinion j, it depends what part of the arm it occurs in. I like to extensively stretch my wrist, shoulder,biceps,triceps etc. before playing and I still have some soreness in arm mainly elbow and shoulder. I like to do rotator cuff exercises to keep my strength in my shoulder up. I have found playing badminton twice a night in winter and baseball twice a night in summer causes a lot of wear and tear on my arm. Overall I'd say it's normal but from what I've read in books, look after your rotator cuff muscles cause it's a hard area to rehab if it gets injured.
Perhaps you are too tense when you play. Make sure that your grip is very loose most of the time; it should automatically tighten (to about 1/2 your grip strength) when you accelerate the racket towards the shuttle. Before & after this acceleration phase of the stroke be sure to loosen the grip to keep the forearm relaxed. You also want to keep the shoulder & upper arm relaxed when hitting your strokes. Altho' ot may seem counter-intuitive, this relaxation should help you generate power ( a knid of efforltless power).