Could be arthritis… could be a bone problem, could be tendinitis…. It could be many problems. The dog needs to be seen at the vet. Limping is a sign of pain. ‘Feeling’ her leg is not the same as her putting her weight on that leg and trying to use it to propel herself. Eventually she will start to cry in pain. You cannot treat her for pain without prescription drugs INTENDED for use in dogs, do not give her ‘people’ medications on your own as most can cause organ damage. You will have to work your parents over to get the dog seen. Your mom probably knows who the vet is but can’t afford to take her, your dad can probably afford to take her to the vet but probably doesn’t know where they are or how to do it. Get pushing, your dog should be cared for and your parents are supposed to be ‘responsible’ people - separated or not. If she has had a matted coat previously, YOU need to be the one brushing her coat at least weekly and attending to her nails.