There are a number of things you can try:
1. Ensure batteries are fully charged
2. Look carefully between the lens and the camera body for any sand or other dirt etc
3. Try turning the camera with the lens facing down and shake to dislodge anything stuck
4. Try removing batteries and memory card, wait 2 minutes and refit
If no luck then we have to try some things that could possibly result in damaging your camera so should only be tried if happy to take that risk...
5. Try thumping the camera into your other hand, by thumping into your hand you are trying to jar the mechanism loose, by using your hand you will hopefully not do it too hard or it will hurt. You may need to do this a dozen or so times in different places to work. I have found the flat of the camera bottom into the flat of your hand best..
6. If the lens is stuck in the out position then remove the batteries and try twisting the lens first one way then the other, do not apply excessive force when doing this or you can break gears, you are trying to reposition not force... Likewise if the lens looks like it is crooked you can try pushing it back into position. This has a higher chance of doing more harm than the thump so please be careful...
7. Dismantle the camera, not for the faint hearted, you need to dismantle the lens assembly into the main body of the camera
If no luck then only other option is a serviceman I'm afraid, be sure to get a quotes as camera repairs can be uneconomical