Tengo un dolor leve en la espalda, pero puedo caminar.

In Spanish, many physical states and symptoms are expressed with tener (to have), not estar (to be).

So:

• Tengo un dolor leve en la espalda = I have a mild pain in my back
• not Estoy un dolor..., which would be incorrect

This is similar to other common expressions:

• Tengo hambre = I am hungry
• Tengo sed = I am thirsty
• Tengo sueño = I am sleepy

Both are possible, but they are slightly different.

• Tengo dolor en la espalda = I have back pain / My back hurts
• Tengo un dolor leve en la espalda = I have a mild pain in my back

Using un dolor makes it sound like a more specific pain or discomfort, while dolor on its own is more general. Since the sentence includes leve, using un dolor leve sounds very natural.

In Spanish, most descriptive adjectives usually come after the noun.

So:

• un dolor leve = a mild pain
• una lesión grave = a serious injury
• una fiebre alta = a high fever

Putting leve before dolor would sound unusual here. The normal order is noun + adjective.

Leve means mild, slight, or not severe.

In medical or everyday health contexts, it is very common:

• dolor leve = mild pain
• síntomas leves = mild symptoms
• una lesión leve = a minor injury

It suggests that the pain exists, but it is not strong.

With body parts, Spanish often uses the definite article (el, la, los, las) instead of a possessive like mi or tu, especially when it is already clear whose body part is being discussed.

So Spanish prefers:

• Me duele la espalda
• Tengo dolor en la espalda

rather than:

• Me duele mi espalda
• Tengo dolor en mi espalda

Using mi espalda is not always wrong, but it is less natural in many ordinary contexts.

Here, en means in or in the area of.

• dolor en la espalda = pain in the back / back pain
• dolor en la pierna = pain in the leg
• dolor en el pecho = pain in the chest

Spanish commonly uses en to indicate where the pain is located.

Yes, absolutely. That is a very common and natural alternative.

Compare:

• Tengo un dolor leve en la espalda = I have a mild pain in my back
• Me duele la espalda = My back hurts

The version with tener focuses on having a pain. The version with doler focuses on the body part hurting.

If you wanted to keep the idea of mild, you could say:

• Me duele un poco la espalda = My back hurts a little

Spanish often leaves out subject pronouns because the verb ending already shows who the subject is.

• Tengo already means I have
• Puedo already means I can

So:

• Tengo un dolor leve en la espalda, pero puedo caminar.

is more natural than:

• Yo tengo un dolor leve en la espalda, pero yo puedo caminar.

You can add yo for emphasis, but it is not necessary.

Because after poder (can / to be able to), Spanish uses a bare infinitive directly, with no preposition.

So:

• puedo caminar = I can walk
• puedo comer = I can eat
• puedo dormir = I can sleep

Not:

• puedo a caminar
• puedo de caminar

This is the normal pattern with poder + infinitive.

Puedo is the present tense of poder.

Full present tense:

• yo puedo
• tú puedes
• él/ella puede
• nosotros podemos
• vosotros podéis
• ellos/ellas pueden

In this sentence, puedo caminar means I can walk or I am able to walk.

Pero means but.

It connects two ideas that contrast with each other:

• Tengo un dolor leve en la espalda = I have mild back pain
• pero puedo caminar = but I can walk

The contrast is: there is some pain, yet the person is still able to walk.

Yes, caminar is very natural here, and so is andar in many contexts.

• caminar = to walk
• andar = to walk / to move around

In Spain, andar is very common in everyday speech, but caminar is also perfectly correct and clear.

So these are both possible:

• ...pero puedo caminar
• ...pero puedo andar

Caminar may sound a bit more neutral or straightforward in a sentence like this.

A little, yes, but the given order is very natural.

Standard version:

• Tengo un dolor leve en la espalda, pero puedo caminar.

You could also say:

• Pero puedo caminar, aunque tengo un dolor leve en la espalda.
• Tengo un dolor leve en la espalda, pero sí puedo caminar.

However, the original sentence is the most simple and natural way to say it.

Espalda usually means back in a general sense. By itself, it does not specifically mean upper or lower back.

If you want to be more specific, you can say:

• la parte baja de la espalda = the lower back
• la zona lumbar = the lumbar area / lower back
• la parte alta de la espalda = the upper back

So dolor en la espalda is general back pain.

Yes, it sounds natural and correct in Spain.

A person in Spain might also say:

• Tengo un dolor leve de espalda, pero puedo caminar.
• Me duele un poco la espalda, pero puedo caminar.

But the original sentence is fully natural, clear, and appropriate.