I don't really know where to begin, but I am nearing the end of my rope with my ex wife. I picked my daughter up to spend the weekend with me last night. Today during a check-in with her mother, I let her know that our daughter got up after I went to bed and cleaned her room. She then asked why I wasn't watching her. Well, I had already put her to bed and she knows to come get me if she can't sleep, but she didn't.
A little while later, my ex calls and asks that our daughter be returned home immediately. This is just one tiny example of things I have to put up with from my ex.
She has said to me, that if she needed to, she would say I touched my daughter after an accident our daughter had at my home. She uses threats like these all the time and threatens to not ever let me see my daughter again. Our divorce decree says my ex has full custody of our daughter, but that was only for medical reasons (but she didn't want to get the extra paperwork to prove it), and that any visitation with me would be up to her.
Am I just screwed, or do I have a chance of getting things changed?

I would go back to court and contest this. Try to get at least SOME custody. I would bring up the threats of you touching your daughter (that's low). Your ex-wife doesn't sound like she has your daughter's best interest at heart. Good luck.

You should have been awarded some kind of visitation during the custody part of your divorce. Go back to the attorney who handled your divorce and have him file a modification if your settlement agreement did not address the visitation with you and your daughter. The visitation is up to the judge, not the ex to determine.

Yes, a very poor visitation ( can I guess you did not show up in court maybe? ) But you go back to court and get specific days and times arranged for your visits.

Thank you for your answers. It has really helped me. It keeps getting worse and I got a message today from her after I sent a message to her husband. The message is this: "are too much of a to deal with me or have you finally figured out who is running the show?" I got this message after I asked her husband if I was going to get to see my daughter today.

After I got off here last night, I got a message from the ex saying " if you want to see her to go find a picture". Then this morning I got one saying I could visit her at noon on Tuesday.

She sounds like she is just up for playing games. Make sure to write down these things, when she said them, and how the communication took place (call, email, text, in person). Show these documents to the judge.

I have saved all the texts she has sent me and informed her husband of what she has sent, and he is NOT happy.

I would imagine.