Have my frights been violated, was i detained illegally do to the color f my skin? Will I be able to get out of this ticket?

at 1:15 am i was going to the store. I was stopped an placed in hand cuffs, the office took my wallet and ran my name. He states; in the opposite direction there was a robbery. I was ticketed for 27-796A of AZ statue, I was in pain I have arthritis in my right knee , I just woke up and was in pain, I was avoiding the dips so i decide to use the road. But about five minutes later . A person who lived where the cops had me detained basically walked past both police cars. on the road, and the officers said nothing . He is white and am a African American. after I was ticked and let go, the supervisor stated if you don't walk on the sidewalk I will arrest you. but again I reminded the officer how he just allowed a causation man brake the law , with out giving a citation a warning or nothing