Dear @Aiden 

Thank you for your question and I am sorry to hear of your plight. Am I correct to say that you had made an uneventful recovery since your hip replacement and this pain that you are feeling is something new that you are experiencing in the last 2 months? There can be several causes for the symptoms that you are describing. These can be broadly classified as intra-articular (from inside the prosthetic joint) and extra-articular (from outside the joint i.e. muscles, tendons,  bone spurs etc.). Sometimes while the pain is felt at the hip, the problem can be somewhere else, most commonly the spine. This is what we call 'referred pain'. However, from what you have described in your post it does not see like this pain is of spinal origin. You have not mentioned any redness in the area or fever which is great because we can rule out infection. A physical examination by a doctor and some basic imaging like an X-ray of the joint may be useful as a starting point to evaluate your pain. However, further imaging such as MRI (excellent for soft tissues like muscles and tendons) or CT (excellent for bone and to assess alignment of the hip joint) may be needed if the X-ray do not reveal anything. My advice would be to take a break from the long walks and get the physio to do a basic assessment of the movements of your hip as well as the strengths of the major muscles around the hip joint. It would be best to get the surgeon who did your hip replacement to have a look at you if at all possible.