My 4yr old male daschund has recently started to seem to be having trouble jumping up on the bed etc. It came on very suddenly, one day he was fine, the next he was hesitating and crying about getting up on the bed. He doesn't yelp when he jumps or anything, he crys because he wants to come up and for some reason he can't jump as high. Is this a sign of an injury or health problem? Is it normal for them to loose some of their mobility at such a young age?
Any thoughts?

There are human illnesses that parallel this -- people who can't jump as high when they get to the age of 20 or 30; etc.

Why don't you take him to the vet?

No, it's not "normal", but it can happen.

The breed is known to have spinal problems, especially intervertebral disk disease (IVDD), due in part to an extremely long spinal column and short rib cage.[8] The risk of injury may be worsened by obesity, jumping, rough handling, or intense exercise, which place greater strain on the vertebrae.

Dachshund - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Dachshund)

I think he was just sore or something, he's back to normal now.

Dachshunds have a lot of back problems so maybe this is why he cannot jump?

Dachshunds should avoid jumping as much as possible. My mother in law has a Yorkshire Terrier with hip problems and she has made 2 small steps to put at the foot of her bed so the dog can get up without jumping.
Perhaps that would be a good idea for you?

Obviously only a vet can tell you what is wrong exactly, it could even be his hips/back/legs/srthritis/strained muscle... possibilities are endless...