These are tiny receptors called mechanoreceptors. (dieselcrew.com)
The scientists discovered that a class of mechanoreceptors in the skin that detect painful mechanical stimuli are part of a feedback circuit in which excitatory neurons that produce the hormone somatostatin are inhibited by neurons that synthesize dynorphin (a natural analgesic molecule that produces effects similar to opiates). (sciencedaily.com)
That being said, the properties of fascia are very unique with several types of mechanoreceptors and if stimulated beyond a certain capacity, can become nociceptors. (blog.nasm.org)