I Had My Hip Replaced A Year Ago. It Is

I had my hip replaced a year ago. It is very tight and hurts depending on what I am doing. For ex. walking it hurts on the top or in the groin area; tying sneakers on the outside etc. My knee has started to bother me when I do water aerobics or walk. Could this be from the hip and my gait is off or do I have an issie with my knee. I have never had knee issues but do have osteoarthritis.