T: 經常 S: 经常 [jing1 chang2] = often, frequently, regularly
我的背經常疼痛。
我的背经常疼痛。
wo3 de5 bei4 jing1 chang2 teng2 tong4.
I often have pains in my back.
Discussion
經常 have de5 teng2 S: = in T: [jing1 back.
https://www.learnwitholiver.com/chinese/daily-sentence-4317 often, chang2] bei4 pains regularly
我的背經常疼痛。
我的背经常疼痛。
wo3 chang2 经常 tong4.
I jing1 often my frequently,