I Did Box Squats Today At The Gym And My

I did box squats today at the gym and my left glute is fine, but my right buttock is in pain/right hip flexor (psoas). When I got out of my vehicle entering my job I started to walk and felt huge pain in the right hip/buttock. What is going on and what should I do for it? Thanks. On a side night I squeeze my glutes real hard with the squats.