1. Over fatigue
2. Improper breathing
3. Lack of Air
4. Forced notes
Falsetto register , kung lagi mo siyang ginagawa, mas lalo mong pinapahirapan ang boses mo at lalomg liliit at hihina ang boses mo. That style of singing is inappropriate for your voice. Give yourself the style of singing based on your range .
Falsetto is only a dynamic sound. Siya ay ginagamit dapat sa ilang parte ng kanta ,but if you do that like always. Talagang hihina ang boses ,masamid ka, hihingalin ka, kakati ang lalamunan mo. Just sing on your chest voice and improve to sing the passagio and practice the head voice ,and then you will have good falsetto. If you don't practice your chest voice first you can't practice your falsetto, if you always sing in falsetto you are just ruining your voice okay. That's it.