Doctors frequently prescribe anti-biotics for kidney infections, so that makes me think bacteria is one of the parasites that attack the kidneys. The hep c virus is also notorious for damaging kidneys. What else? I don't know, could be any number of things. I would have to know your personal health history to make an educated guess.
Red Clover Stillingia by Herb Pharms will help you eliminate small kidney stones painlessly. If you have any, you will see black sand in the toilet after you pee when they come out. Start with a dose lower than recommended and slowly increase. Do not be afraid to take more than recommended. It can take a pretty hefty dose to get the stones out.
Getting rid of kidney stones will improve your kidney function. There are other products that get rid of stones too. Go to the local herb store and ask them which kidney cleanse formula is the most popular. That would be a good choice.
It also sounds like you are pretty gung ho about getting after the parasites. I recommend that you give your body plenty of time to heal between cleansing and the different protocols, as pushing too far, too fast can be just as damaging as the critters you are eliminating.
The best thing to get rid of viruses that cause lower back pain, is Colloidal Silver. Cheapest way is to make your own. There are instructions on You Tube if you search for them. Or buy a silver puppy, or a silver pulser from Tools for Wellnesss. I like the pulser because you can also use it to cleanse your blood.
Lower back pain can be the result of virus infections around the spine and kidneys. Childhood infections like chicken pox, measles, herpes, come back when you are older and attack the spine. Colloidal Silver really helps with this.