221(g) can be issued for variety of reasons depending on the case...The only thing that you can do is submit the relevant documents (if you were given to submit any documents, letters) as soon as you can and hope for the best. If you were not asked to submit anything, you just need to wait...If you do not hear back within a month or so, you can always write to the embassy/ consulate using email ID and request status of your case. If you are asked to submit passport after you submit documents, just submit it.