What is the easiest way to go to the US from Pakistan?

You cannot just go to the US; you have to be sponsored, either by a qualified relative or by a US employer on the basis of a valid job offer. Your son who is a US citizen can of course go to the US without any of that but since he is a minor, you would need to accompany him and in order for you to come to the US lawfully and remain here, you need to be sponsored. Your son would only be able to petition for his parents once he turned 21.

Unfortunately, there really isn't a good way: Your son could return to the US at any time, but he is still a minor, so he cannot go by himself. He can come here for college when he is older, but he will be able to sponsor you, his parents, only when he reaches 21 years of age. There is nothing your son can do for you now to bring you all to the US, unfortunately.

If your son is a US citizen, you must first attempt to obtain his US passport by going to the US consulate in Pakistan. He may come to the US at anytime, but, as a minor, you may have to arrange for him to live with relatives when he arrives here. Unfortunately for you, the fact that you are the parent of a US citizen gives you no right of entry. You will have to have an independent basis for coming to the US. And in this regard, bad economic conditions in Pakistan sadly does not count. When he turns 21 years old, your son can file petition for you to obtain a green card. There might be other viable options for you and your wife to come to the US, and in that regard, I suggest that you have a telephonic consultation or Skype consultation with an experienced immigration attorney, to whom, you must provide in advance all the necessary documentation about your background.