I used swing before and my forearms are so painful that need to see dr and physio
I don't like swing and finally changed to ameda which is much better
One more thing, u try not "dup" 低頭太多 (eg. I always 低頭 looking when pumping) which dr and physio told me.
They said arms painful may due to neck problem. I tried not "dup" 低頭太多 and changed to lie down on bed to feed my baby instead of holding her (so that no need to "dup" 低頭太多 ), now my painful relieved . My forearms were so painful for 3+ months before