I am currently going through detox and withdrawals, I have been placed on multi vitamin and ensure for weight loss. I start suboxone treatment tomorrow. I have been having a slight burn when urinating with a clean urine sample no infections. What could b

Fluid intake. If a urine culture was negative for infection, you may be experiencing urethral irritation and, for this, adequate fluid intake may relieve the urinary burning. SHoot for at least two quarts of fluids per day to ensure a good urinary output.
Not to worry. Dehydration is considered, In this situation ensure you are drinking water at least until urine is a little lighter than normal. When detoxing, urine is eliminating waste and that can burn at the urethra. This will not likely present any problem starting Suboxone but tell your doctor about it.