i've noticed while chain punching that my left seems to be slowere than my right and also less powerfull what training do you suggest i undergo to help my left arm?
Sounds like there is a problem in relaxing your left arm / shoulder.
I think you should try doing single arm chi sau just on the left arm , and just generally doing a lot more punching of the focus mitts /pads on only that left arm.
Don't worry about it too much , with me its the other way round , my left is faster than the right , although my right is more coordinated.
A lot of people would have the same problem whether due to a past injury or just carrying tension on that side. It might fix itself up or it might not , don't be too concerned .
Its not as if when you have to use it on some low life that they will be saying " Dude you hit like a truck , but that left one was a bit slow ".
We are not perfectly built machines , we have to work with what we
have .
Probably if you examined yourself closely you would find that maybe one of your ears is larger than the other , or your feet what ever , except for some blessed individuals few of us are physically perfect.
See if you can even up the punching speed of your arms , but don't become obsessed by it. I've tried pretty much everthing , and one of mine is still faster than the other.