表示“打算”,“即将”,“肯定”或“命令”时,可以用be going to这个情态动词,be going to有现在式和过去式两种形式,如：
They are going to have the entrance hall painted white.
The ice is going to crack.
I am not going to have this.
I am going to oppose the proposal.
My sister is going to have a baby.
It is going to rain.
Now you are going to hurry.
如果把be going to变为一般疑问句,只要把be动词提到主语前即可,所以你给出的句子要改成：
Am I going to play football?
希望我能帮助你解疑释惑.