Hiya flowerladyne! You've been given a lot of great advice. :) Here's what I advise that you do right away, as you're learning about the rest of your options:
Get a good probiotic. I recommend Primal Defense, but it's expensive. There are others, just make sure it's either refrigerated or has a good delivery system so the microbes make it past the stomach alive. PD isn't refrigerated but they ahve a patented way of making sure the microbes are alive and populate your gut. You need to do this to offset the damage done by Antibiotics
Joint pain is almost always due to poor digestion (is your tongue often coated? have cracks? teeth impressions along edges?), too much red meat, weak liver, imbalanced diet, congested colon. Thus, bowel management, liver flushes, and increasing the power of your digestion is key for you.
Sore knees can mean a lot of things. I'm a Capricorn so I'm prone to them myself, but they usually only get sore after a lot of tennis. :) If it's due to circulation, then castor oil packs will help with that, as will de-tox baths, both of which are described here on CureZone.
So make colon cleansing/bowel management a priority, schedule at least 2 Liver Flushes
once you get your bowels moving, and I have notes on digestion, bowel management, etc. if you haven't seen them already - I post them a lot. :)