What do you mean "have to work too hard to make it move"?

You aren't giving us much to work with here.

So far my thoughts have been in no particular order:

1. Get rid of the tower.

2. Improve your fitness and strength.

3. Reduce the weight of the load you are attempting to carry on the bike.

4. Get some advice on your fit -- even posting a picture of you on the bike might be a start.