Hayes, the 8th overall pick in the 2019 NBA Draft, is being sued for assault and battery by Sofia Jamora, who claims he roughed her up on multiple occasions during their relationship ... including the night he got into a scuffle with cops.

According to the lawsuit, obtained by TMZ, Jamora claims they started dating in October 2020 and the NBA stud first got violent with her on Valentine's Day 2021, violently abusing her in a Dallas hotel room.

In the docs, Jamora claims she traveled with Jaxson for his NBA game and shared a hotel room, and when he returned to the room he flipped out when she joked about a lack of Valentine's Day flowers. She claims he cussed her out, hit her with a suitcase he tossed across the room, physically prevented her from leaving the room and broke down a bathroom door to rip her phone out of her hand.

In her suit, Jamora claims Jaxson apologized for the Valentine's Day 2021 incident and swore he would never get physical with her again ... but she says more abuse followed as their relationship continued.

According to the docs, Jamora claims Jaxson, his two dogs and his cousin were staying at her Los Angeles home on July 27, 2021 when he got violent again.

In the suit, Jamora claims she left Jaxson at the home during the day while she was at a photoshoot and came home to find her dog severely injured, blaming the bite wounds on Jaxson's much bigger dogs. She says Jaxson was "passed out from a drug-induced stupor" when she got home, and while he was asleep she put his dogs in crates.

In the docs, Jamora claims Jaxson eventually woke her up at midnight and asked what happened to the dogs before flying off the handle. She says they got into a verbal argument, which escalated into Jaxson allegedly threatening for his cousin to rape her.

In her suit, Jamora claims Jaxson got physical with her and her puppy, throwing the pup to the ground and grabbing and shaking her, to the point where she told him he was hurting her. She says she locked herself in a bathroom, but he broke the door down and roughed her up.

Jamora claims Jaxson chased her all around the house and the property, grabbing her multiple times, tossing her around and dragging her down some stairs. She says he became enraged and started breaking anything he could get his hands on.

According to the docs, Jamora claims she locked Jaxson out of the house but he broke in through a window and she texted her cousins, begging them to call the cops.

In her suit, Jamora claims cops eventually arrived and Jaxson started interfering with the police investigation, getting into an altercation with officers where he was tased.

TMZ broke the story ... Jaxson was arrested that night, and he recently entered a no-contest plea for a resisting arrest and false imprisonment charge.

Jamora is suing Jaxson for assault, battery and infliction of emotional distress ... and she's going after him for damages.