[trikey]

The only way to check this properly is to remove the brake disc and inspect the components, someting may have broken causing it to become tight.

If all is well, give everything a good clean and refit the disc, release the tension on the nut at the handbrake lever, then adjust the handbrake at the wheel until the disc cannot move then back off the adjuster three clicks.

Now adjust the tension at the lever until you get 2-3 clicks at the handbrake, I use this method and never have an issue.