Why does my Schnauzer mix keep whining?

[Sarah]

I have a Schnauzer mix that's getting up in his years (around 7-8 years old now) . I've had him for almost 5 years now. Lately he's been starting to whine ALOT (mostly during the night time I've noticed) even though he gets his daily exercise everyday.. He's always been the hyper/whiney type, but it's never been this bad.. And because of him getting older, I found this to perhaps be of concern. Health visits to the vet are quite pricey, so I don't have the money to take him.. If anyone can be of help so as to know of anything, please let me know.