Rihanna to Chris Brown -- I'll Ride with You NO MATTER WHAT

9:42 AM PT -- A rep for Brown says the singer did NOT write the Instagram post ... insinuating that it was drafted by an imposter.

You really buyin' that?

Hours after Chris Brown was accused of cheating the system, he got some serious support from Rihanna ... who rode shotgun with the singer following a recording session in L.A..

The two were pictured leaving the L.A. studio together around 4:30 AM ... following an angry statement from Brown in which he said his life is PURE HELL.

We broke the story ... prosecutors believe Brown LIED about doing community service -- and could face serious jail time for allegedly participating in a conspiracy to dupe authorities.

But last night, Brown reportedly took to Instagram to unload about the situation ... telling his fans he can't relax because the stories about his life are constantly being covered on TV, radio and everything else.

Brown's frustrations are obvious -- "Im wise I can handle the hate but enough is enough, yo!!"

He continued ... "Im a human being and I honestly think I deserve respect Im sick of being accused ... Im tired yall Just don't understand Ive been going through this sh*t since I was 19 years old .. You cant sit here and tell me to calm down, when am I gonna get a positive outcome out of anything I do?"

"Im not gonna sit here and play victim, Im just tired of this sh*t ... I pray every day and night for a new outcome ... and just when everything seems to be going good some new sh*t happens."

And then Brown -- a convicted woman beater -- had the balls to write, "A day in my shoes is a day in hell, believe it or not!"

A hearing in the community service matter is set for today in L.A. at 2:00 PM PT.

Stay tuned ...

CHRIS BROWN'S ENTIRE INSTAGRAM STATEMENT

"I love ya'll but ya'll getting repetitive telling me to relax. no I'm not gonna relax. Im makin an album right now ... and ya'll tell me not to pay attention to it. How can I not when it's on my radio, TV, and everything else ... even if I did relax I wouldn't stop hearing about it .. ya'll are everything to me ya'll know this but telling me to ignore it is like telling me to walk around with a blindfold and stick earplugs in my ear .. Im wise I can handle the hate but enough is enough, yo!!

Yes it bothers me but it's not my main focus! my music is ... and when I speak on it .. its because I want people to know how I feel .. yes they talked about Jesus ... but "him" I am not him, not even close!!!

Im a human being and I honestly think I deserve respect Im sick of being accused ... Im tired yall Just don't understand Ive been going through this sh*t since I was 19 years old .. You cant sit here and tell me to calm down, when am I gonna get a positive outcome out of anything I do?

When can I get that feed back?

Im TIRED do you read me Im tired!!!!!! Im not gonna sit here and play victim, Im just tired of this sh*t ... I pray every day and night for a new outcome ... and just when everythnig seems to be going good some new sh*t happens.

A day in my shoes is a day in hell, believe it or not!