Meditation is by no means guaranteed to be relaxing. I've been on several retreats, and wile they were always rewarding, they were rarely relaxing. That's just a popular myth.
The ultimate "goal" is transcendence, which untethers your consciousness from your physical body and is quite a liberating experience.
The catch to it all, is that you can't have a goal while meditating, other than to be present in the moment, which is an admirable goal in itself.