It's the result of an inflamed fascia in your foot. Fascia aren't muscles or ligaments; rather, fascia is stretchy, strong connective tissue that helps stabilise you. This particular one (the plantar fascia) starts at your heel bone, runs along the bottom of your foot, and connects to your toes.The plantar fascia is super important because it supports the arch of your foot, making it possible for you to balance, no matter what you're doing. "It elongates and contracts depending on the shoes you wear, the activities you do, the impact on your foot, and your body weight," says Dr. Sutera. Without it, your arch wouldn't be able to move the way it needs to in order to support you.But when the fascia becomes inflamed or irritated due to wearing shoes without the right arch support for the activity you're doing (whether that means standing for long periods in heels or running in worn-out sneaks with no arch support), your heel lights up in pain, especially in the morning or when you first stand up. That's because while you're resting, the fascia relaxes and the irritation relaxes a bit, too. But as soon as you stand up, the fascia contracts again, re-starting the inflammation. If left untreated, the pain can spread up your Achilles tendon and begin to affect your knees.If you're already feeling the pain, Dr. Sutera says there are a number of things you can try at home to soothe it. Bonus: Some of these tricks may also help prevent the problem from happening in the first place. Here's Dr. Sutera's advice.Change up your footwearPlantar fasciitis tends to hurt really bad in the morning when you first wake up. Although the pain may disappear after your first few steps, it often then gets progressively worse throughout the day. Staying completely off your feet is probably not an option, but wearing shoes with good arch support can help take some of the pressure off your fascia so it can heal.It's also worth noting that bad shoes are among the main causes of this issue to begin with. You don't have to swear off flip flops forever, but it's worth checking in with the shoes you're wearing most often. Are you wearing the same kind of shoes every day? If so, try switching it up. Are the insoles worn out? Do they even have supportive insoles of any kind? If not, there are many orthopedic inserts that can make your favorite shoes work better with your feet.