Wiktionary
vb. 1 (context sports English) To feel the burning sensation arising in a muscle being intensely exercised; often used as an exhortation to extend oneself in physical exercise. 2 (context sex English) To feel the vaginal or anal pleasure or burn felt during sexual intercourse.
Wikipedia
Usage examples of "feel the burn".
Tristan could feel the burn of the gash start to diminish, and he watched as the wound closed itself.
Only then did she notice the blood dripping down her arm to splash scarlet dots on the sidewalk, and feel the burn of the two-inch gash that slanted across her forearm.
And I could feel the burn on the right side of my face, though it wasn't visible there because I'd probably turned my head.
He could feel the burn of the metal even through his thick gloves and wondered if the engineer was still alive inside.
When the red glow was halfway up the strip of metal, and perhaps she was beginning to feel the burn on her fingertips, she clicked off the phaser and reset it.
It's convenient most of the time, but just occasionally it is extremely useful to feel the burn as you walk across hot coals.
He could feel the burn all across his back, and could detect his medicircuits going to work on the damage.