I have one kidney and get 60g protein a day, i do intense 45min workouts 6 days a week, could i take one 20g protein shake on those days to recover?

Yes.: That should not be a problem. Make sure you get regular preventative exams with your primary physician and he/she monitors your kidney function periodically (annually or biannually). Good job with the exercise. It sounds like you are motivated to stay in good health. :-). Btw, was kidney removed electively or due to disease or is it non-functioning since birth? Important to know history.

Protein ingestion: Animal protein definitely increases blood flow and blood pressure thru kidneys. Having a solitary kidney at age 21 already creates a high likelihood that your kidney's blood flow and blood pressure are increased. Increased blood flow and blood pressure will enlarge glomeruli (the blood filters) and strain them. Increasing dietary protein will increase strain. Eat 50-60 grams per day only.