Cassie Ventura says there was a painful, physical side-effect from all the “freak-offs” Diddy had her doing with male escorts … urinary tract infections.

The singer testified in court Wednesday she would take opiates after the freak-offs to numb herself from very painful UTIs.

Cassie told the jury the UTIs would give her a burning sensation, and she got them so often that antibacterial medication stopped working, and she needed more powerful pills … and turned to opiates.

She said she tried to avoid kissing the male escorts because it seemed too intimate — but Diddy would tell her to kiss the male sex workers.

Cassie testified Diddy even asked her to do a freak-off on her 29th birthday … pulling her out of the Blind Dragon karaoke bar in West Hollywood, and using his security team to take her to the freak-off.

She talked about some of the aftermath from Diddy’s 2016 assault on her in a hotel hallway — the full, unedited 15-minute long video was shown in court and is now released — and she testified Diddy tried to lure her back by telling her he was getting arrested.

Cassie and prosecutors read some text messages in court … they said a message from Diddy read, “Pls call, I’m surrounded.” Cassie testified she texted back, “please stay away from me” and Diddy responded, “I’m getting arrested.” Diddy was NOT arrested.

She told the jury Diddy would get physically violent with her at freak-offs too … sometimes in the presence of the male escort they hired. She said the escorts would ask her how she was doing after Diddy put his hands on her, and she says the violence happened “too frequently” in places like New York, Los Angeles and Miami.