Retired general William C. Westmoreland's $120 million libel case against CBS was delayed for at least two days today after he suffered what his attorney, Dan M. Burt, described as "lower-back pain."

Burt, noting that Westmoreland had made 121 parachute jumps during his 36-year military career, said the general had been hospitalized several times with back problems over five years.

Westmoreland had been scheduled for his seventh day on the stand and his fourth day under increasingly tough questioning by CBS attorney David Boies. The trial involves a 1982 CBS documentary that charged Westmoreland with being part of a conspiracy to alter enemy troop data to maintain support for the Vietnam war.

David Henderson, a friend of Westmoreland, said the general's last serious back trouble occurred in 1981, when he was bedridden for four to five weeks.

It was not known how serious the current problem was.

"It could be the strain of sitting there, day after day, being inactive," Henderson said. The trial is in its eighth week.

Boies said today that Westmoreland's lawyers asked him weeks ago whether he would consider breaking into his cross-examination of the general for appearances by other prosecution witnesses. Boies, saying he did not want his cross-examination of the general interrupted, refused, and did so again today when Westmoreland's lawyers repeated the request.

Boies said that if Westmoreland were not well by Thursday, he would begin his defense, offering what he called "background music" for CBS' side of the case.