I've read about this same problem before, and I think it is your recoil rod assembly that is binding. If you didn't get it back in the right position when reassembling it, it can drop down and bind the slide. I've tried searching for the thread that I read before, and I can't find it.
If I remember correctly, the person who had this problem before did several things. One, hold the pistol upside down, and try pulling back on the slide and pulling forward on the barrel, and see if that might free it up. Another thing is to pull down on the take down levers, so that they are in the most downward position, pull the trigger and keep it pulled, and see if you can remove the slide (this takes some manipulation, unless someone can help you.) The thing is, if the recoil rod assembly has come off, it may be wedged between the barrel and frame.
I've also read that one person took out the striker (you can get to it with the slide fully retracted) but that may or may not solve this particular problem.
I hope someone will post some better advice/solutions for you. Good luck and I hope you get it back in working order!