I'm far from an expert (outside of my own personal experience), but here is what I think based on my own experience with your symptoms (and I have had just about all of your symptoms at some point in recent years):
I get very irritated after eating fatty foods or other hard to process foods. (could be candida and/or parasites, and of course both affect your digestion, especially digestion of fats)
I am fatigued all day, every day, no matter the quality of sleep (again, could very well be candida and/or parasites)
My shoulders and knees hurt for no reason, especially my knees (I have the same problem, for me it was all sorts of random joint pain. Another sign of candida and/or parasites, along with being too acidic (common result of candida/ parasite presence))
I have dark circles under eyes and it is chicken skin is texture (MY BIGGEST ISSUE) (Over acidity along with the above)
I am unable to gain weight or muscle( 20 lbs. underweight) (This could definitely be parasites)
Dry and sometimes very itchy skin (Candida)
Muscles ache way too much after exercise and go away slowly (A sign of over acidity. When I was at my worst, I would stay sore from a workout for days and days afterward. The reason for this is that exercise produces lactic ACID and other acidic substances which cause the sensation of muscle soreness. A normal body is able to flush away the lactic acid in good time, making the soreness last only a couple of days. For those of us who are too acidic, the soreness can last WAY long.)
Anxiety and stress (candida/parasites)
White coating on tongue that is not painful (candida)
Acne around mouth when I dont brush coating off tongue (This is what made me suspicious of Candida)
Poor short-term memory (candida/parasites)
Inability to concentrate (candida/paraistes)
White marks on fingernails for no reason
I drink a lot of water and eat a healthy diet.
(SIDE QUESTION) Is it ok to use Mag 07 or colosan by itself without colonics after a Liver Flush to clean out stones left behind in colon?
In order to be sure that you are free of parasites, you need to use either Miracle-Mineral-Supplement or go on a serious parasite cleanse using niclosamide, prazi, etc. Forget about that Wormwood /clove nonsense, which does nothing to help a serious infestation. I am doing both, but Miracle-Mineral-Supplement helped me get rid of not only large parasites (which I didn't even know I had) but also blood parasites.
My opinion is that until you are sure that you are parasite and candida free, you are basically wasting your time with doing Colon Cleanses alone. Whatever you manage to get out will just become reinfested again, and the toxins will build up again just like before. At least that's my view.