I've had back issues my whole life. I started having pretty severe knee issues starting 6 mos ago. I've caused them both to 90% clear up with the following:

• Stretch your lower back with gravity: Get some crutches, set them to "uncompfortably tall", put their feet about 10" from a wall, and about as far apart as you would were you using them normally. With your back lightly touching the wall (the crutches should be vertical), put your feet out in front of you so you're making about a 120-deg bend at your waist. Relax your back muscles so that your weight is, as much as possible, only supported by the crutches, letting your lower back relaaaaaaaaax and stretch. If you're doing it right, you'll probably get some satisfying "pops" in your lower back. That, along with how great this (should) feels, motivation to do this regularly should be easy to find.
• Two variants of the same exercise. I'll assume you have a "problem leg" (the one with the knee that hurts):
  • Facing up stairs, climb to the next step, one-foot-at-a-time, leading with the problem leg. Focus on using only the strength of this leg to bring your weight up to the next step (which, if you have my problems, will be nearly impossible initially because of the pain provoked by this. If this is painless and easy for you, you don't have my kind of knee problemns.) Now step back to the starting stair in the same way: lead with problem leg, one-foot-at-a-time. Repeat this, get a rhythm goin'. Do much.
  • Stand on a stair facing down-stairs and do the same.
• With a couple of dumbbells, do a penché with either leg on the ground and the other up in the air, and the weights way down near the ground, using them for balance. Really get down there, get your other sexy leg up in the air, waay up straight. gracefully switch legs, do the same, repeat. It helps to try to keep the leg that is not on the ground aligned with your arms (together, they make a straight line), as you go up and down, focusing on using your lower back muscles to do this.