Terrific read. I felt the adversity and pain and joy...
That is what makes a trip a TRIP!!!!!
Bet your knee was just being over used and making a fuss to you. Had you been on the trail several days it more than likely would have eased up pain wise and hopefully swelling as well. Had it myself too many times ... pushing miles. Pop that knee in cold streams and rub it and keep breaks short so it doesn't stiffen up. That is for the evening and morning.
Yes .... get vigilant on making your load lighter. Your knees will thank you!
20 to 24 pounds should be very doable for a three night romp in the piney and aspeny and hilly woods.
Shug