Hi Rita!
I don’t think it would be wise for anyone to disseminate advice given your brief background unless they have a medical background, and then they probably wouldn’t without more info. 🙂 No one wants to be responsible for giving out advice that ends up in injury!
Do you have plantar fasciitis or something else? My first thought would be to get that cleared up before working on exercise, and honestly I would go for light strength training for an extended period of time (under the guidance of a physio) before moving onto HIT. Many (though not all) HIT exercises are high impact and you should have strength and stability for the affected joint systems. Remember everyone is different and it may take some work figuring out what works best for YOU! Good luck!

I used to get plantar fasciitis from wearing and exercising in low-quality shoes. I solved this problem by getting some custom insoles made to fit inside my training shoes. I went to a ‘foot doctor’ who made a cast of each of my feet, and then manufactured custom insoles that completely supported my feet in the right places. After wearing these insoles for just a few days, my plantar fasciitis was gone !