Hayden Panettiere Seen Using Crutches Months Before Death, Blamed Back Pain

Hayden Panettiere wasn't feeling well in the months before her death ... even needing crutches to get around at one point.

Photogs caught up with the star at LAX back in March ... she was moving gingerly and leaning heavily on the mobility devices.

Hayden told the photog she was dealing with some pinched nerves in her lower back ... and she promised she was on the mend before slowly stepping into her waiting SUV.

This clip falls right in line with what we've heard from sources ... one of whom told us she'd been complaining of back pain regularly over the past year.

Shortly after this clip was shot, Hayden embarked on the publicity tour for her memoir "This Is Me: A Reckoning" ... before passing away Sunday.

As we reported ... Hayden's friend called 911 from a residence in Greenville, South Carolina just before 2 PM. The caller told authorities the actress was unresponsive and in cardiac arrest.

We obtained dispatch audio of responders sending medics to her location to perform CPR on someone who overdosed ... and our sources say they attempted to resuscitate Hayden using "advanced cardiac life support." She was officially pronounced dead at 2:32 PM.

The Greenville County Coroner is expected to perform an autopsy Monday to determine her cause and manner of death.

Hayden was just 36 years old.