everytime I play without scoring, I seem to be better, with the score, I keep thinking of it and I tend to make mistakes also, my coach say my body is stiff. so any ideas how to relax my body?
try playing with players one level below your skill level. without the pressure, you can spend more of your attention to focus on relaxing. when you have learned to relax then go back to the better players.
do you normally keep score or your partner/opponents do? i find that i tend to keep an eye on the score more when i'm keeping it and that might add a bit more to the pressure, especially when it's a competitive game. try letting others keep score for you so that you can just concentrate on playing.
You could be trying to win too much. Stop playing games for a while and concentrate on training and doing well in the training. When you become confident doing your shots, then play a few more games.
I agree with the 'having fun instead of focussing on winning', it's great advice, but at least in my experience very hard to employ. I'm intensely competitive... sure can't do it. So what I do, is when I'm losing, I mentally reset the score. I let the other person keep score and convince myself it's 0-0. I think, "It's a new game, I'm going to come out like a whirlwind and scare them and take the upper hand." It doesn't always work, but it helps. The mental game is so important, and it's good to get caught up in the competition... but not in the negative aspects. It's hard to focus on the thrill itself, but once you can (...I'm still working on that, blah) it will greatly enhance your performance.
First and foremost, you need to have fun. If you don't, you will eventually burn out from playing. This is why people leave the game, not just badminton, any game/sport/hobby. When a person no longer has fun, he will eventually lose his passion for the game. You need to first go back to having fun playing the game, then incorporate your competitiveness back in. Then you will win on both fronts. You will have fun (again) and play better, improving your game. It's a win-win situation.