are you sure about swollen muscle? It is a prominent hard bump
could I ask you one more thing? I havve recently began to be more active. saturday I went to train and on Monday I have very sharp lower back pain when twisting or bending forward. I still went to gym on Monday night and did a fitness session and I was fine. Today I still have the back pain and my neck is a bit stiff and I can feel pain when turning my neck left and turning my neck back.