I'm thinking there is some stasis to cause the " stiffness improves with use" but not sure how to explain the different rear leg pain and neck pain and the weak urine flow. Kidney deficiency comes to mind to explain the urinary changes but not sure how to fit it all together. Possibly kidney and blood deficiency? I was considering a tonic with moving properties and thinking of trying Bu Zhong Yi Qi Tang.
Does this sound appropriate?