Hi,
Welcome to Healthcaremagic.com. 
I had gone through your question I can understand your concern about discoloration of urine. 
 As you said you have brown colour discoloration of urine it can be because of three different issues. 
1) 
Urinary tract infection ; painful and smells foul during micturation (pee). It can be associated with lower 
abdominal pain. You need a course of antibiotics to get it treated. 
2) Normal discoloration because of high concentration of urine it can also be painful while micturation, you  need to take plenty of fluids for it. 
3) Most important is related to 
liver problem, it is a pain less yellow or dark yellow (discoloration) may be confused with brown. If you see any yellowness in your eyes, face etc. You need to get it evaluated. It can be dangerous too like 
Hepatitis B, C. You need to get a urine test done( 
bilirubin) for proper satisfaction. 
Hope the answer to your query, visit us back in case you feel any further assistance needed.. 
Regards 
Dr Muzaffer Hussain Parray.