Any two animals will have differences in their preferences and behaviours.
If you are ever concerned about your pet's behaviour or health, it's a good idea to get a professional opinion. The very best thing would be to consult a veterinarian. The vet will do a physical assessment and ask questions that will help with the diagnosis.
If you don't have a access to a vet, you can contact one through my site on the question page. Just use the teal form. You do have to pay for the answers, but not as much as you probably would to take your pet in to see a vet.