Check with your doctor as the cause of this may be medical in nature....like a medication that you are taking, or a hormonal imbalance. Either way, your doctor should be able to help you with this.
I don't get aroused what can I do?
First stop saying " don't " - that sabotages you right from the start. Watching porn might help. Buying toys to experiment with might also help. If these things fail- see your family doctor. He/she may have a solution for you.
Asking anonymously defeats the purpose. If you're male the solution is likely to be much different than if you're female.
There may be clinical or psychological reasons which can be dealt with very simply. You need to speak to a professional.
If you are male, get your testosterone levels checked.