Disturbances shattered the calm of Easter morning in several towns in the occupied West Bank and in East Jerusalem today after a second wave of complaints of illness struck more than 200 schoolgirls in two Arab villages.

Military authorities said a hand-grenade explosion in Nablus injured two Israeli soldiers. An Arab youth was shot in the hand, apparently by an Israeli civilian, after a stone-throwing incident near Hebron.

Palestinian sources said two other Arab youths were shot by Jewish settlers near Nablus, but this was not officially confirmed.

Israeli authorities imposed curfews on several towns and villages in the West Bank as a result of the unrest, said that they sent medical teams to the two villages where the illness was reported and blamed the disturbances and the illness on "political provocation" by Palestinian nationalists.

In Amman, Jordan, Palestinian leader Yasser Arafat expressed urgent concern over what he described as Israeli-instigated disturbances and violence on the West Bank, but he and key advisers indicated that the tensions there would not cause them to rush into unqualified acceptance of President Reagan's Middle East peace proposal. Details on Page A20.

It was the second Easter in a row marked by violence here. Last year a wild shooting spree by an American-Jewish immigrant in the Dome of the Rock mosque in Jerusalem's Old City left two Arabs dead and nine others wounded.

The mysterious illness was reported in two widely separated villages--Yatta, south of Hebron, and Anabta, east of Tulkarm. More than 100 girls in each village complained of headaches, dizziness and nausea. Israeli officials said some were taken to West Bank hospitals and others to Israeli hospitals in Jerusalem and Tel Aviv.

The symptoms were similar to those that struck more than 300 Arab schoolgirls in the Jenin area of the West Bank last week. At that time, Palestinians charged it was a deliberate poisoning by Israeli authorities and Jewish settlers in the territory. Israelis suggested that the girls had been made ill by Arab extremists seeking to incite trouble among the Palestinian population.

Thursday, Dr. Baruch Modan, the director-general of the Israeli Health Ministry, said an investigation had found no evidence of poison or other chemical substance as the cause of the illness.

Although several Israeli border policemen and two Israeli women soldiers had complained of similar symptoms, Modan said he believed it was largely the result of "mass hysteria."

The same kind of charges and countercharges followed today's reports of a recurrence of the illness. Israeli officials said they believed the reports of the illness in Yatta and Anabta were an attempt to "exploit very clearly" the uproar over the earlier cases.

"We find it difficult to free ourselves from the feeling that these are attempts similar to those in Jenin to create disquiet on the streets, using the girl students and this phenomenon," said Shlomo Ilya, the head of the Israeli civil administration in the West Bank.

"However, we are treating it as a medical case," he said.

Asked in a telephone interview whether he believed the schoolgirls had fabricated the symptoms of the illness, Ilya replied, "Yes. It is like people in the area are taking part in a big show."

Ilya said about 240 girls in the two villages complained of the illness today.

Palestinian sources, however, put the total number at 380 and quoted Wahid Hamadalla, the deposed mayor of Anabta, as blaming the second instance of the illness on the Israeli government and Army.

As Christian pilgrims attended Easter services here and elsewhere in Israel, there were also these developments:

* Two Israeli civilians and a tourist were injured in widely scattered stone-throwing incidents in the West Bank. Three other Israelis were slightly injured by stones thrown in Jerusalem's Old City. This afternoon, security forces used tear gas to break up an Arab demonstration in the Old City.

* Arab students held a vigil near the Dome of the Rock mosque to commemorate last Easter's shooting spree by Alan Harry Goodman, a Jewish immigrant from Baltimore.