My small dog has become increasingly aggressive when near his crate and we want him to come out, mostly to go on a walk. Today he wouldn't move a muscle when I called him, so after trying to call him in a playful way, stern way, nice way I lifted the back of his crate so that he came out and closed the door so he couldn't go back in. I told him to sit, which he did, and I put the first part of the harness over his head. After I saw that he was still sitting and nice I started rubbing his head and saying good boy and after a few seconds he started growling and jumped on me and bit me a little (it looked like he realized what he was doing and didn't fully bite me, but I do have 3 teeth marks in my leg and some scratches). I looked up dog trainers and they all seem to be upwards of $200-300 per hour which we can't afford right now, but I don't want him to get worse and bite the kids. I'm so confused since nothing has changed except that we are all home more of course, but he generally likes walks, isn's injured, and the harness is loose fitting so I have no idea what to do at this point. Help!