My gut tells me to focus on using a lax ball to tack the hamstring muscles while sitting and going through leg extension ROM.
Also, focus on rolling side to side the back of the knee, and the area’s just above and below. Make sure you’re rolling as far as possible so that you’re almost rolling the side of the knee.
Hit up the suprapatella pouch with a roller and the front of the tibia.
Let me know if you feel any relief from about 15-20 minutes of the above.