The reference here means to go against your conscience. God pricks the conscience, the impressions of which are often resisted. See the following examples:
“And he said, Who art thou, Lord? And the Lord said, I am Jesus whom thou persecutest: it is hard for thee to kick against the pricks” (Acts 9:5).
“ ‘And he [Saul] trembling and astonished, said, Lord, what wilt Thou have me to do? And the Lord said unto him, Arise, and go into the city, and it shall be told thee what thou must do’ (Acts 9:6). No doubt entered the mind of Saul that this was Jesus of Nazareth who spoke to him, and that He was indeed the long-looked-for Messiah, the Consolation and Redeemer of Israel. And now this Jesus, who had, while teaching upon earth, spoken in parables to His hearers, using familiar objects to illustrate His meaning, likened the work of Saul, in persecuting the followers of Christ, to kicking against the pricks. Those forcible words illustrated the fact that it would be impossible for any man to stay the onward progress of the truth of Christ. It would march on to triumph and victory, while every effort to stay it would result in injury to the opposer. The persecutor, in the end, would suffer a thousand-fold more than those whom he had persecuted. Sooner or later his own heart would condemn him; he would find that he had, indeed, been kicking against the pricks.” Sketches from the Life of Paul, 23, 24.
“Their knowledge of the truth makes it hard for them to indulge in sinful pleasures, for they cannot altogether put out of the mind the claims of God upon them. There is a feeling of impatience at the restraint which is thus imposed. They try to get away from this admonitory voice; but they find themselves kicking against the pricks, piercing themselves through with many sorrows. Oh, that they would come to the Fountain of living waters before they shall have grieved away the Spirit of God for the last time!” Testimonies, vol. 4, 626.
“When you and your husband left the sanitarium, it was because you were not willing to humble yourselves before God. In leaving the sanitarium you acted very unwisely. What influence will this have on the patients and nurses who as yet know nothing of the matter? What interpretation will they place on your actions except that you thought yourself abused? But it is not true that you have been abused. God has been dealing with you, and you have been kicking against the pricks. It is not you who has been wronged, but the Lord Jesus. He has been dishonored by your course of action. Are you willing to meet your record in the judgment?” Manuscript Releases, vol. 18, 267, 268.
[All emphasis supplied.]