What can I do about a gas pipe that is in my way?
As Tester101 mentioned, a flexible hose is not suitable for concealing in the wall.

Similar to plumbing that is in the way, the pipe needs to be re-routed and moved.  Depending on your location, this might be something that is permitted by the home owner or it might require a licensed technician to complete.

Unlike water where a small leak is unlikely to kill anyone, an incorrectly plumbed gas line can be deadly and as a result, unless you have experience working with gas lines, it is best and safest to call someone in to complete this for you.