LLPSI, Capitulum vercesimum quartum, l47?

Salvete,

I’ve been making good progress through this chapter but have become bogged down by line 47.

Syra: “Etsi valet, certe tergi dolores passus est.”

Could somebody please offer me a translation of this. I’ve really no idea of the intended meaning and have been stuck at this point for a couple of days. Is Syra saying that Marcus is a pain in the neck?

“Although he is fine [now], he certainly has suffered back pains.”

There is a marginal note connecting ‘passus est’ with the deponent verb ‘patior’, of which it is the perfect (“has suffered”). ‘Tergi dolores’ is the direct object.

Thanks.