Did you restart vim after configuring the .vimrc file? (Or reload it with :so % while editig it?) Is your vim a recent version?
By coincidence, I started using vim-go just a few days ago. I followed the instructions in the readme exactly and, with firstly installing pathogen, it just worked for me without any trouble whatsoever.
execute pathogen#infect()
syntax on
filetype plugin indent on
map <F2> @v
nmap <cr> :mak editor<cr>
nmap <F12> :noh<cr>
set autoread
set autowrite
set cc=80
set columns=160
set cursorline
set hlsearch
set incsearch
set lines=50
set modeline
set number
set tabpagemax=100
set spell spelllang=en_us
winpos 550 72
let maplocalleader = ","
let mapleader = ","
au Filetype go nnoremap <buffer> <LocalLeader>k
\ :exe 'GoImport ' . expand('<cword>')<CR>
" Search for selected text, forwards or backwards.
vnoremap <silent> * :<C-U>
\let old_reg=getreg('"')<Bar>let old_regtype=getregtype('"')<CR>
\gvy/<C-R><C-R>=substitute(
\escape(@", '/\.*$^~['), '\_s\+', '\\_s\\+', 'g')<CR><CR>
\gV:call setreg('"', old_reg, old_regtype)<CR>
vnoremap <silent> # :<C-U>
\let old_reg=getreg('"')<Bar>let old_regtype=getregtype('"')<CR>
\gvy?<C-R><C-R>=substitute(
\escape(@", '?\.*$^~['), '\_s\+', '\\_s\\+', 'g')<CR><CR>
\gV:call setreg('"', old_reg, old_regtype)<CR>
let g:go_auto_type_info = 1
au FileType go nmap <Leader>ds <Plug>(go-def-split)
au FileType go nmap <Leader>dv <Plug>(go-def-vertical)
au FileType go nmap <Leader>dt <Plug>(go-def-tab)
au FileType go nmap <Leader>e <Plug>(go-rename)