shock problem

Ok I am rebuilding a shock from a 2004 rm250 and when I took it apart it was really hard to separate the body from the shaft assembly so I used a mallet to get it out and thought it was just hard to get out. Then I go to reassemble and no oil will flow through the piston or rebound circuit, so it just pushes oil to the other side of the shock body. I don't know if this is something I can fix or if I need to take it to a shop.