My brother in law has moderate weakness and pain in all of his muscles , also note urine test had mod blood , any thoughts ? thanks

Need more info: Blood in urine always needs to be investigated to rule out stones or tumor. Other symptoms are vague and do not point to a particular diagnosis. It would be prudent to see a doctor for an in-person evaluation.

Possible UTI: No info on how long these symptoms have been occurring, but a urinary tract (doesn't always 'burn') could cause this, as could other issues. He would do well to see his dr, have some labs drawn, with an exam and good history. He may need antibiotics or referral to a urologist for further workup.

See a doctor: Blood in the urine is not normal and may be associated with significant disease. This sign combined with muscle aches and weakness is a concern and should be evaluated by a doctor ASAP. You do not mention if your brother in law is taking any medication that might cause muscle injury or if he has been exercising a lot. These factors could help explain the problem