What Causes Pain In Groin Area And Back In A Arthritis Patient?

Question : Hello, I has Front Hip Flexor and Groin pain and aching that started back in early October. I was an runner and also was playing a lot of Tennis and competitive Ping Pong. I noticed pain increasing and one day I noticed that my right side Groin/Inguinal area was slightly bigger than my other side. I could also feel a little nodule or something as I stood for a while. I went to the urgent care and they had me do a Hernia test. They weren't sure if it was or not. They sent me for an Ultrasound. The Ultrasound came back negative for a Hernia or any other Issue with the Testes, Scrotum or Inguinal area. I went to my GP and he checked the area thoroughly and said it was 100% not a hernia. He diagnosed me with Hip Flexor and Groin Strain. He said the right side being slightly bigger was either the way I have always been or the area was a bit swollen due to the ligaments and muscles being swollen. He felt the little nodule and said it was my "cord" which he said is just more prominent on that side. He said to stop exercising for a while and see a Physical Therapist. I went to a Hernia Specialist to be sure and he did every possible check of the area and said it was 100% no Hernia. He said it just felt a bit weaker on the right side and that some men aren't asymmetrical there and that the little thing I felt was just my "cord" more prominent there but all is good. My last blood test was clear back in May 2015. I also did acouple of Urine tests and all were fine. My doctors said it was likely Hip Flexors. I have a small amount of Arthritis building in my hip, said my GP from an X-Ray. I need an Orthopedic doctor to explain if it is possible to have the Psoas or some muscles near the hip to become inflamed or swollen in the Inguinal/Groin area. Please let me know. The Physical Therapist did help some. I have Plantar Fasciitis which the Physical Therapist thought could have been contributing to my Hip/Groin issues as he said my Pelvis was not aligned 100%. Please let me know. Thank you