When you know you have overdone it and your back hurts, it doesn’t usually come as a surprise. But, when you are experiencing back pain that you cannot easily explain, it can help to know some of the lesser known causes.

Here are 10 things that can cause back pain.

1. Too much stress.

When you are experiencing stress, you might find that the added tension can cause muscle aches, and even muscle spasms. Todd Sinnett, a New York City chiropractor and the author of 3 Weeks to a Better Back, stated, “If you’re uptight for a long period of time, that muscle tension can lead to aches and spasms.” Back pain caused by stress typically shows up in the neck and shoulders, or the lower back. Sinnett recommends relaxation exercises, taking a walk, or trying yoga.

2. You wear high heels too often.

A commitment to high fashion can lead to back pain, if your idea of fashion includes high heels. William Suggs, a certified personal trainer and licensed sports nutritionist in New York City states, “If you must wear heels for work, invest in a nice pair of walking shoes for the commute and change at the office.” Wearing high heels can put strain and stress on the lower back, which can lead to chronic pain.

3. You eat too much junk food.

A recent study published in the Asian Spine Journal found that about 1/3 of women and ¼ of men who reported back pain also reported gastrointestinal problems. There is a definite link between nutrition and back pain, as certain foods that contain high amounts of unhealthy fats and sugar can cause inflammation. Suggs suggests, “Always have a protein like lean meat or beans, a good whole grain like brown rice, and vegetables.” Avoid processed foods and make your food choices as “clean” as possible.

4, Your pants are too snug.

Some fashion trends, like skinny jeans, can cause back problems. When pants are too tight, they can constrict your body, limit your range of motion, and cause strain on your back, neck, and shoulders. Skinny jeans and pencil skirts are thought to be the biggest culprits. Aim to find clothing that has some stretchiness and fits more comfortably. If you can’t fit a finger under the waistband, your clothes are too tight.

5. You sit down too much.

By now you have probably heard that it is not good for you to sit down too much. Suggs says, “Inactivity is one of the most detrimental things you can do to your body. Your muscles get used to being in that seated position, so they tighten up.” Suggs recommends getting up and walking around at least a few times per day to stay loose and combat back pain.

6. You don’t quit smoking.

A study conducted recently at Northwestern University found that those who smoke are more likely to experience back pain, and less likely to recover after back issues. This is thought to be related to the slowed circulation that comes with smoking.

7. You have a weak core.

Having a strong core can help reduce back pain. Suggs stated, “If your abs are weak, your lower back has to work harder, which can lead to back pain.” He suggests monitoring your posture and paying attention to keeping your core engaged throughout the day.

8. You don’t drink enough water.

Within your spine, the discs that are supporting the bones are made up of a substance that is 90% water. Maintaining good hydration is critical for good disc health. When you are dehydrated, those discs can flatten and provide less support.

9. Your hips are not properly aligned.

When your lower back is not properly balanced, you can end up with significant back pain. Suggs states, “It affects how your body responds to certain moves and will be different for everyone. Your doctor can evaluate your whole body and detect potential imbalances.” Being properly aligned is very important for preventing back pain.

10. You have a urinary tract infection.

Back pain and flank pain can be a sign that you have an urinary tract infection or kidney infection. If you have any other symptoms, such as an urgency to urinate or failure to empty your bladder, or any pain during urination, see your doctor immediately.

You may not even realize that these things can lead to back pain. But if you are suffering and can’t figure out exactly when you hurt your back, consider these possible causes.