Background and purpose Nonspecific neck pain (NNP) is a common idiopathic disorder in the general population that affects the trapezius muscle (TM) and blood supply, thereby compromising the fascial system. Myofascial reorganization (MR) is a physical therapy technique that can influence the dynamics of local fluids reducing excessive muscle tension and capillary constriction, and increasing local blood flow. This study aimed to investigate whether MR improves peripheral muscle oxygenation. Methods This was a quasi-experimental study with an intentional non-probability sample. Fifty participants (women: 36, men: 14) with and without NNP were assigned to either the experimental group (EG: n = 25, with NNP, subjected to MR) or the control group (CG: without NNP, no MR intervention). TM oxygenation was measured using near-infrared spectroscopy (NIRS) before and after a single intervention. In addition, functional disability (CG: 5.48 ± 5.58%/EG: 21.12 ± 7.73%) and neck pain were measured using the neck disability index. The pain pressure threshold (CG: 70.49 ± 32.29 kgf/EG: 51.08 ± 27.65 kgf) and pain intensity (CG: 0.76 ± 1.56/EG: 3.28 ± 2.35) were also measured. All participants were evaluated and reassessed after 10 min. Results The results revealed that immediately after 10 min of MR, the EG exhibited an increase in the oxyhemoglobin level of the medium fibers of the TM (0.72 ± 1.47 vs. −0.14 ± 1.33 mmol/dL, p = 0.01). Conclusion The findings indicate that application of MR for 10 min increases the tissue oxyhemoglobin level in the TM of the group with NNP compared to the CG without NNP.