Pain during Achilles rehab exercises doesn't necessarily mean it’s bad. Some discomfort is acceptable.
What matters is how intense the pain is, how quickly it settles, and how it feels over the following 24 hours.
A painful Achilles doesn’t seem to respond well to stretching. Maybe because the tendon is already sensitive and repeatedly stretching it may just keep irritating it. Before stretching, ask whether the Achilles actually needs more flexibility in the first place.
Complete rest can make an irritated Achilles feel better. But feeling better doesn’t mean it’s ready to run again. The tendon needs the right amount of load. Enough to stimulate tendon remodelling without stirring it up.
If your Achilles is painful, the first step is to settle it down. That might mean temporarily stopping running, walking up hills or other activities that are aggravating it. But settling the pain isn’t the end goal. It merely creates a better environment to start rebuilding from.