The 28-year-old aggravated the problem in his five-set loss to Jack Draper in the Australian Open second round on January 15th and then retired injured midway through a doubles match while partnering Nick Kyrgios the following day.
"Been struggling for a little while with this... Probably my toughest challenge to date," Kokkinakis said on X with a picture of himself in a hospital bed with his right arm in a sling.
"Trying to find answers to an ongoing pec injury that I haven't been able to fix. Let's see how this goes. Thank you for all your ongoing support."
Kokkinakis, who reached a career-high singles ranking of 65th in 2023, is currently 84th and has one title to his name.
He has enjoyed much more success in doubles, capturing a Grand Slam trophy with Kyrgios at the 2022 Australian Open.