Help!!!

So my boyfriend and I have been having sex for not long and he recently asked me to start doing more. I don't know why but touching him and trying to move is like... impossible feeling. How am I supposed to move during sex? And how do I touch him? I just feel so bad because he always tried his best to make me feel great and loved and I haven't been doing the same. And now I need to at least try but it scares me. Please help!