CAN= The verb "can" in an affirmative sentence is pronounced /kən/or /kn/

I CAN ONLY IMAGINE= It's impossible for me to know.

WHAT IT WILL BE LIKE...= The complete sentence is: I can only imagine what it will be like when I walk by your side.
As you can clearly see, this is not a question, but a statement, so there is no inversion. Many people (depending on their mother tongue) tend to use an inversion with interrogative words, always. In English we only use an inversion if it's a question, but not if it's not a question, so be careful. Here are some examples:
1- Who are you? (question, inversion)
2- Tell me who you are (no question, no inversion)
1- Where do they live? (question, inversion)
2- I don't know where they live (no question, no inversion)
1- What will you do? (inversion)
2- I can only imagine what I will do (no inversion)
In this song, you can find more examples of both direct and indirect questions, for instance:
- Will I dance for you, Jesus? (direct question, inversion)
- I can only imagine what my eyes will see. (no question, no inversion)
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The LIKE in this sentence is not the verb, but the preposition:
- What's your father like? – He's very tall and handsome.
- What is heaven like? – It's a place where everybody's happy and everything's perfect
In this context, the sentence "I can only imagine what it will be like..." means "I don't know what I will feel" (because he's talking about emotions here).

WHEN I WALK BY YOUR SIDE= In biblical language, talking about God, this sentence expresses the idea of company, being with (not necessarily walking), so this sentence here means "when I am with you".

JESUS= /dʒi:zəs/

IN AWE OF YOU= (poetical or old fashioned) The word AWE /ɔ:/ expresses the strong emotional reaction before something/someone really powerful: an intense feeling of admiration or terror; so today we use as part of two very different words: "awesome" (=fantastic) and "awful" (=horrible). The meaning in this context is positive, so "in awe of you" means more or less "feeling overwhelmed by your sublimity, power and beauty".

STILL= (Adjective) quiet, without movement. If something is still, it's not moving. Don't confuse this adjective with the adverb or the connector:
- Everything stood still (adjective) = Nothing was moving
- I'm still waiting for her (adverb) = She hasn't arrived yet
- He's horrible. Still, he's my friend (connector) = He's horrible but he's my friend

TO MY KNEES WILL I FALL?= If you fall to your knees, you kneel down. The complete sentence is: "will I stand in your presence or will I fall to my knees? This change in the correct order of the sentence (placing the adverbial "to my knees" before the verb) is called a hyperbaton, and it's a literary figure of speech that makes the sentence more beautiful and poetical (but if you are a student of English and say this in normal language then it's not beautiful, it's simply incorrect)

HALLELUJAH= /hæləlu:jə/ (Hebrew word from the Bible, also spelled Halleluyah, Halleluiah or Alleluia) A joyful word of praise to God, something like "glory be to God" or, in modern language, "God rules!", "He's the best!". The strange J that we pronounce /j/ (like an Y) here is an old spelling that has survived because it was used in the standard Bible for the English (King James Version), but you can also use the I (or even Y), which fits better with its pronunciation. Spellings without H are also possible because you can also pronounce this word without /h/.
We can also use this word to express a great joy for something good that happened, specially after a long wait (e.g. "halleluiah! you finally passed your driving test!")

WILL I BE ABLE TO SPEAK AT ALL?= The verb "be able" is an alternative to "can", specially in cases where the verb "can" is not possible. We only have two forms for this verb "can" (present and future) and "could" (past and conditional). Any other tense will be formed with "be able to" (will be able, has been able, is being able, etc). The phrase AT ALL is used to emphasize questions and negatives:
- I don't like it at all
- Do you love him at all?

STANDING IN THE SUN= It is very common to use the sun as a symbol of God. This sentence also brings echoes of the angel from Revelations, who appeared in the skies "standing in the sun" (Rev 19:17). Many people think this sentence is "Standing in the Son" (The Son = Jesus, the son of God), but that doesn't make much sense, it should be "Standing before the Son". The confusion between SUN and SON is possible because both words have the same pronunciation /sʌn/, but the context and the Bible clearly favour "sun" here.

WORSHIP= Ardent devotion; adoration. If you worship God, you love Him intensely.
There is also a more "mundane" usage of this word, which is the ceremonies, prayers, or other religious forms by which this love is expressed, but in this context he is not talking about formalities and procedures, he's talking about intense love, which is the real worship (Hos 6:6)