Former senator John G. Tower has submitted his resignation as U.S. negotiator in the strategic arms reduction talks in Geneva for "personal reasons," sources inside and outside the government said yesterday.

Although the resignation caught some White House officials by surprise, friends and colleagues of the former chairman of the Senate Armed Services Committee said they had been aware for some time that he was unhappy in Geneva and was preparing to leave the post he took 14 months ago.

At an international meeting in Munich last week, Tower, 60, said he was frustrated with Soviet intransigence and "did not intend to make a career out of being a negotiator," according to a source at the meeting.

Other sources said Tower's decision was sparked by a combination of factors, including a realization that he was not in line to become secretary of defense -- the Cabinet job the Texas Republican has sought since President Reagan was elected in 1980.

White House and State Department spokesmen refused to comment yesterday, but some sources said an announcement is planned for later this week. Tower is in London and is not expected in Washington until Wednesday, State Department sources said.

Tower's resignation comes as the fourth round of the Geneva negotiations ended last week with Washington and Moscow blaming each other for the lack of progress. The next round, scheduled to start May 8, is expected to be more active since Soviet leader Mikhail Gorbachev has put progress on arms control at the center of the agenda for his next summit meeting with Reagan, and his first in the United States.

Although Tower's appointment was criticized by arms control advocates and some congressional liberals, many believed he was the best prepared of the three U.S. negotiators and had gained stature with the Soviets because of his mastery of the arcane technical details of strategic weaponry.

Several White House officials said they were surprised by Tower's resignation. Some administration sources yesterday mentioned Ronald Lehman, a former Tower deputy, as a possible successor. "He's the primary candidate that would provide continuity on the job," one official said.

Lehman, however, was recently named one of two deputies to White House national security affairs adviser John M. Poindexter, and one source said it was doubtful he would leave that position.

Tower told listeners in Munich last week that the Soviets were rigid in their position and that he saw little prospect for an arms control agreement. Friends said he found the life of a negotiator dull compared with the hurly-burly of politics. He also has complained about gaining weight as a negotiator, telling an acquaintance: "It's hard to get a bad meal in Geneva."

Other sources said there were family pressures, including a desire, after 24 years in the Senate, to make more money in order to help his children.

He also "felt he was out of the mainstream of Republican politics," one colleague said, and was under pressure to help his party in the upcoming Texas gubernatorial election.

Underneath it all, one source said, was Tower's realization that Defense Secretary Caspar W. Weinberger would not be leaving his position.

"He told me he didn't see Cap moving out," one source said yesterday, "and it wasn't worth staying over there [in Geneva] waiting."