Ice Ice Baby!

At my school in Maryland we have our hard BJJ training days on Mondays and Wednesday. I usually teach a class or two and train in a couple classes including the advanced Jiu-Jitsu classes on these days.
Last night was a rough one. In the advanced class we did a lot of shoulder exercises and my shoulder is still recovering from an AC joint separation I suffered in June so it was very painful. Not only is there still pain but my arm is still very weak. I pushed through but by the time I left I could barley move my arm. This was not just because of pain but even more so it was just wiped out. Almost complete muscle failure. I new I was going to have to do something extreme in order to be able to train tonight.
I needed to start loosing weight for the next tournament season. So at the beginning of last month I started running first the first time since I was young. I have been running almost every day since. After about 2 weeks I started getting shin splints, my knee started hurting, and my calves were pulled. A friend of mine suggested doing an ice bath. Ice baths are done in all professional sports and my friend was quick to say "if you want to train like a professional you got to do the ice bath". They are absolutely miserable but I must say it did help. After one time my shin splints were gone and my knee felt fine. After my second one my calves healed. It was a miracle. I am now a true believer in the ice bath and have been doing them somewhat often.
From the beginning my friend said he does the ice bath submerged up to his neck but I could not bring myself to do it. I only went in waist deep for my legs. After last nights advanced class I decided to stop being a wuss and just do it. I went in up to my neck so that my arm and shoulder were submerged. I must say that this was absolutely the worst thing that I have ever done in my life.
When you go in only up to your waist it only hurts for about 2 minutes and then everything numbs up. When you go in up to you neck it hurts the whole time. It does get mildly better after 2 minutes but if you move at all it still hurts. Also the chattering of the teeth never goes away. At one point I started getting a brain freeze like I just ate something really cold.
I did make it the full 20 minutes but I don't know how often I will be doing the full body. I will say that my shoulder feels better then if I would have just iced it normally. However it was horrible and am not sure if it was worth it or not.