“What is wrong with me?”

I have had bad health for about 5 years and they can't seem to figure out what's wrong. They said I have COPD asthma and allergies but I have a feeling it's something else and so does my family. The last year I've been getting really weak where just getting out of bed and walking a few feet to my bathroom has been bringing me out of breath and I work out and also have a job where I'm constantly on my feet I also suffer from joint, muscle, head and chest pains constantly and it can last for days without stopping. My skin will bruise almost just but touching it all my medication has stopped working and they have tried putting me on different ones they never work I always have constant chest pain and headache I very rarely get a break from. My doctors have done many tests but don't know what's going on and why I am getting worse I've gone downhill badly in the past year and I'm worried I won't be able to fight it I just want to figure this out so I can live normally without being in pain every day constantly, please help me.