I want to get the data for masses of galaxies, more information about them can only be helpful. Can anyone point me to a site where I can get this sort of information?
As a starting point, I would suggest searching on VizieR for catalogues of galaxies. E.g. select "Galaxies" in the "Astronomy" menu (on the right-hand side of the initial form) and put "Masses" in the "Find catalogs" search box (the upper one, the lower one is for searching by position which is less useful here).
In the results section, the elliptical icons on the right-hand side allow you to see roughly what the sky coverage is for the catalogue. Once you select a catalogue, you can take a look at what fields are there.