An emotional Tracy Morgan, fighting back tears in his first interviews since he was injured in a crash with a Wal-Mart truck that killed his friend a year ago, vowed to return to comedy on Monday but said he wonders whether he can be funny again. The comedian, who starred in the television show “30 Rock” and the late night comedy sketch “Saturday Night Live,” held a cane and was accompanied by his lawyer as he was interviewed on NBC’s “Today” program.