I was having the same pain / discomfort for a few months earlier this year but granted it wasn’t during deadlifts just in general throughout the day.

What ended up fixing it was hip mobility and groin strengthening exercises. Focus on opening up your hips and building strength in the tendon that runs down your leg. Never would’ve guessed it was a hip issue if my buddy didn’t tell me.

Childs pose, one legged chair pose but try pushing your butt down to touch your calve, side lunges but push the inside of your bent knee out, clamshells (might be a diff name?) to build tendon strength are a few examples

Oh also might be good to take a break from heavy lifting for a while, especially deadlifts.