После падения мне было больно ходить.

Because после normally requires the genitive case.

• после = after
• dictionary form: падение = fall
• genitive singular: падения

So:

• после падения = after the fall / after falling

This is a very common pattern in Russian:

• после урока = after the lesson
• после работы = after work
• после дождя = after the rain

Падение is a noun meaning a fall or falling.

It comes from the verb падать = to fall.

So instead of saying something like after I fell, Russian can use a noun:

• после падения = after the fall / after falling

This sounds compact and natural. It is similar to English expressions like after the accident or after the fall.

Because Russian often uses the dative case for the person who experiences a feeling or condition.

Here, мне literally means to me, and the structure is roughly:

• мне было больно = it was painful to me / I was in pain

This is a very common Russian pattern:

• мне холодно = I am cold
• мне жарко = I am hot
• мне грустно = I am sad
• мне трудно работать = it is hard for me to work

So the person is not the grammatical subject in the way English usually does it.

Because this is an impersonal construction.

Russian often expresses physical or emotional states without a normal subject like I or it. Instead, it uses:

• the experiencer in the dative: мне
• a state word like больно
• sometimes a form of быть in the past or future

So:

• Мне было больно ходить
  literally: To me, it was painful to walk

This is completely normal in Russian.

Because the sentence is in the past tense.

In the present tense, Russian usually does not use the verb to be:

• Мне больно ходить = It hurts to walk / It is painful for me to walk

But in the past tense, Russian does use it:

• Мне было больно ходить = It was painful for me to walk

The form было is the past tense neuter singular form of быть. In impersonal sentences like this, Russian commonly uses the neuter singular form.

Here больно means painful, it hurts, or in pain depending on the context.

In this sentence, it means:

• было больно ходить = it was painful to walk

This word is often used in impersonal expressions:

• Мне больно = I am in pain / It hurts
• Ему больно сидеть = It hurts him to sit
• Было больно смотреть = It was painful to watch

This is different from adjectives like:

• больной = sick, ill
• болен = ill

So больно is about pain, not necessarily illness.

Because the pattern here is:

• кому-то было больно + infinitive
• it was painful for someone to do something

So:

• мне было больно ходить = it was painful for me to walk

Other examples:

• мне было трудно дышать = it was hard for me to breathe
• ему было страшно говорить = he was afraid to speak
• нам было приятно познакомиться = it was pleasant for us to meet

The infinitive expresses the action that caused difficulty, pain, fear, and so on.

This is a very natural question, because both can relate to walking.

The short answer:

• ходить = walking in general, being able to walk, walking as an activity
• идти = going somewhere in one specific direction, one specific instance

In this sentence, the meaning is general:

• walking hurt
• it hurt to walk

That is why ходить fits better.

If you said мне было больно идти, it would usually sound more like:

• it was painful for me to go / to keep going
• a more specific occasion or trip

So after an injury, мне было больно ходить is the more natural choice if you mean walking in general was painful.

Yes, and the literal translation helps show the grammar:

• После падения = after the fall
• мне = to me
• было = was
• больно = painful
• ходить = to walk

So a very literal version is:

• After the fall, to me it was painful to walk.

That sounds unnatural in English, but it shows how the Russian sentence is built.

Yes, absolutely.

That version means:

• After I fell, it was painful for me to walk.

Compare the two:

• После падения мне было больно ходить = more compact, noun-based
• После того, как я упал, мне было больно ходить = more explicit, clause-based

Both are natural. The original sentence sounds a bit more concise and slightly more formal or written.

No, Russian word order is fairly flexible, but the original order is neutral and natural.

Neutral version:

• После падения мне было больно ходить.

You could also hear:

• Мне было больно ходить после падения.
• Ходить после падения мне было больно.

These all mean roughly the same thing, but the emphasis changes:

• starting with После падения highlights the time/background
• starting with Мне highlights the experiencer
• starting with Ходить highlights the action

For a learner, the original word order is a good default.

Not in the past tense.

• Мне больно ходить = present
• Мне было больно ходить = past

So if you are talking about the past, было must stay.

Russian often omits to be in the present tense, but not in the past or future.

It can be understood either way in English, depending on context.

Russian uses the noun падение, so literally it is:

• after the fall

But in natural English, the idea may be:

• after falling

Both match the Russian well. The exact English wording depends on the broader context.