Islamic law does not constrain scientific research but encourages research, observation, and knowledge. God the Almighty says, “As also in your own selves: will yet not then see?” [51:21], and “Say: “Are those equal, those who know and those who do not know?” [39: 9]. However, Islamic law does set certain restrictions to practices that lead to corruption and harm, or to those which contravene customs and public morals.
If spiritual response therapy which aims to treat psychological disorders through releasing past painful memories that may cause psychological problems is a science that is recognized by a specialized academy or research center, then it is permissible for you to practice it while observing professional ethics. It is impermissible if it causes corruption.
The manner of exploring the unseen through the swinging motion of the pendulum as mentioned in the question, is not a recognized form of psychological therapy. Rather, it is a form of divination practiced in pre-Islamic Arabia which involved the casting of arrows. One arrow bore ‘do, another ‘do not do’ and a third was left blank. A person would then choose one of the arrows without knowing the instructions it bore. If the lot showed ‘do’ he would embark on the matter in question. If it showed ‘do not do’, he would desist from his purpose which he believed is harmful. But if the lot was blank, he would repeat the process until it showed one of the other two. By such means, he would seek to know the unseen and this is prohibited. God the Almighty says, “Forbidden to you (for food) are: dead meat, blood, the flesh of swine, and that on which hath been invoked the name of other than Allah; that which hath been killed by strangling, or by a violent blow, or by a headlong fall, or by being gored to death; that which hath been (partly) eaten by a wild animal; unless ye are able to slaughter it (in due form); that which is sacrificed on stone (altars); (forbidden) also is the division (of meat) by raffling with arrows: that is impiety” [5:3] and “O ye who believe! Intoxicants and gambling, sacrificing to stones, and divination by (arrows), are an abomination,--of Satan’s handiwork: eschew such (abomination), that ye may prosper” [5:90].