Need some advice . MooShi , my 6 yr old fur baby , has been having a hard time jumping up on furniture lately .And once in awhile if she has been sitting a certain way she will limp for a short time after getting up. Is this normal for a dog her age and any tips advice on a good supplement to give her . I hate to see her struggle in any way and feel she is still so young to be going threw this .Any suggestions would be greatly appreciated.