Where can I get Per Capita Income data of states in the USA? Also which are the sources often used in econometric or macroeconomic analysis and how reliable are they?
BEA Person Income per capita for USA or states
St Louis FED can pull up this data for you. https://fred.stlouisfed.org/series/A792RC0A052NBEA
For your second question, it really depends on how you define personal income. A recommendation is to check the statistical agencies definition of personal income and see if it matches up with your analysis/ project.