If it's just contact pain, it should be possible to rig something up that keeps things from touching the knee. The orthosis should help, they've served my brother pretty well after he dislocated both knees in separate incidents. You might be able to use the old one by attaching some padding to the top and bottom so it stops sliding, although I would recommend locating someone who knows what a proper fit is first so you can ask them if that will make it stop working. A proper fit is presumably one where it stays in place without pressing the sore part.
Ibuprofen is recommended for pain and inflammation, so take that.
I do not expect electromagnets will help much with this; legitimate magnetic messing about is still experimental and mostly concerned with nerve-related stuff. There may be some lab out there with some magnetic contraption that would make it stop hurting, but not actually fix things.
Dietary supplements and such are largely bullshit. Protein is good for muscle development and suchlike, but it's reasonably likely you're getting enough for that already. Wearing the ortosis while exercising is a good idea.- Are there food additives / meds / devices to wear during exercise that can help prevent further injury? Does eating hyaluronan / chondroitin sulfate help? (Okay, if the jar itself says "is believed to to play a role in cartilage formation and repair", probably not, but it doesn't hurt to ask.)
The meds you mentioned have not been properly evaluated for long-term side effects. Do not take them.