Selma Blair

is hurting "all the time" amid painful health battle.

The 51-year-old star — who has been in remission for

multiple sclerosis (MS)

since 2021 after being diagnosed in 2018 — is suffering with the effects of

Ehlers-Danlos syndrome

, which is a group of inherited disorders affecting connective tissues, including your skin, joints and blood vessel walls.

Taking to Instagram, she said in a lengthy and candid video: "

I hurt all the time

. I say that for you people that hurt too. Like, I get it. And for all of us just aging, it hurts."

While most people can stretch to help with muscle pain, it's not an option for Selma.

She explained: "So, the Ehlers-Danlos will make me really, really, really stiff."

The

Cruel Intentions

actress added: "So, I get some injuries, but this is nothing that's like horrible, scary stuff or anything.

"It's one of those extra things that turns into a chronic thing and you have to watch because people think stretching is so good for you.

And I'm technically not allowed to stretch

."

Selma is trying to stay positive despite feeling "sad" over the impact of her condition, which leaves her stiff and tired all the time.

She said: "But I am doing well. I'm doing well. Tired. When people say, 'What do you want to do with your life?' It still makes me sad that I just want to sleep."

And although she feels "lucky" in some ways, there are still drawbacks she can't ignore.

Selma explained: "There's no complaining. But I don't know if I'll ever have the coordination or balance or stamina that I want to. Still lucky. Still grateful. Still okay. But it's still a bummer."

The

Legally Blonde

star is using her platform to ensure people with disabilities can still lead a normal life and have the same experiences as everyone else.

Asked if her activism — including helping President

Joe Biden

celebrate the new

Americans with Disabilities Act and the Rehabilitation Act

— has given her a new purpose, she told

Parade

magazine: "Sure, I did have those nights where I'd wish, 'Whoa I'd love to have more roles.' Of course, I would have loved some type of stardom.

"But I was not tied to it in that way. I never thought of an Oscar speech in my life. Never crossed my mind. Then I felt like I needed to take that next step in my life and do what feels good. So, Yo hice."