A 58-year-old male presents to clinic with complaints of lower back pain. He states the pain has been going on for about 3 weeks without radiation down either leg. He is unsure of any inciting events and describes the pain as sharp and rates about a 5/10. Physical exam reveals point tenderness at the right sacroiliac joint. Straight leg raise test is negative and patient has full strength with sensation intact bilaterally. Osteopathic structural examination reveals a positive standing flexion test on the right, a superior ASIS on the left, and a superior PSIS on the right. Given the exam findings, which of the following is the most likely diagnosis of this patient’s somatic dysfunction?