1. File in the state that you incorporated your business. 2. File in the state that you are domiciled in.
The absolute answer to the letter of the law is to file short year returns for California and Mass. because anywhere you were located meant that the company was temporarily based in that state. But, realistically this is stupid and the states aren't going to really care about you because you don't make enough to be worth their time.
So there you have it.
This said, some theoretical answers to your question (I am not an attorney, and none of this is anything beyond my conjecture): http://www.irs.gov/businesses/small/article/0,,id=98277,00.h...
http://www.corp.delaware.gov/paytaxes.shtml
If you search on Bing/Blekko/Google/Wherever for 'CPA ___[your current city]____' you'll find some good resources. Well worth the investment in time.
It's not worth your time to try to figure this out yourself unless you're one of the crazy people (and I count myself in this group) who actually enjoy digging through the various statutes, regulations, and treaties covering such matters.
But here is what you need to Google: "IRS pass-through entity".