If you do not have any uncommitted change then do a hard reset from Team > reset > (select Hard option) do a pull request again. find all the conflicted file(file with red diamond icon) Resolve any conflict (manually edit the file, or use merge tool),
then right click on all(one by one ) conflicting files, select "team", then select "Add to Index".
(if every conflict is resolve then there should not be any conflict(red diamond) icon. before trying to commit anything make sure all the conflict is revolved)
now you should be able to commit to git again